Anti-PCNA monoclonal antibodies and use thereof

ABSTRACT

The present invention provides a monoclonal antibody or an antigen-binding portion thereof having increased binding affinity to cytoplasmic PCNA and blocks its interaction with NKp44. The present invention further provides use of the antibody or an antigen-binding portion thereof in the treatment of diseases associated with elevated expression of NKp44, such as cancer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Phase of PCT Patent Application No.PCT/IL2017/051351 having International filing date of Dec. 14, 2017,which claims the benefit of priority of U.S. Provisional PatentApplication No. 62/434,532 filed Dec. 15, 2016. The contents of aboveapplications are all incorporated by reference as if fully set forthherein in their entirety.

FIELD OF INVENTION

The present invention is in the field of monoclonal antibodies.

BACKGROUND OF THE INVENTION

Alternative splicing of NKp44 RNA results in three splice variants whichcan be divided by the presence of an immunoreceptor tyrosine-basedinhibition motif (ITIM) in the cytoplasmic portion of the receptor.NKp44-1 isoform has been shown to be ITIM positive, whereas NKp44-2 and-3 isoforms are ITIM negative. The ITIM mediates the inhibitory natureof the NKp44-PCNA (proliferating cell nuclear antigen) interaction.

There is a need for developing agents highly specific for the NKp44-1 toPCNA interaction, with the ability to block this interaction.

SUMMARY OF THE INVENTION

The present invention provides monoclonal antibodies or antigen-bindingportions thereof having increased binding affinity to PCNA.Advantageously, the antibodies described herein are neutralizingantibodies. The present invention further provides compositions, kitsand methods, such as for the use of the antibodies or antigen-bindingportions thereof in the treatment of diseases associated with NKp44,specifically NKp44-1. The present invention further providescompositions, kits and methods, such as for the use of the antibodies orantigen-binding portions thereof in the detection and diagnosis ofnon-nuclear PCNA-associated diseases, such as cancer.

According to one aspect, the present invention provides an antibody oran antigen-binding portion thereof comprising three heavy chain CDRs(CDR-H) and three light chain CDRs (CDR-L), wherein:

CDR-H1 comprises the amino acid sequences selected from SEQ ID NO: 1(GFSFNI) and SEQ ID NO: 21 (IYAMN),

CDR-H2 comprises the amino acid sequence as set forth in SEQ ID NO: 2(RIRSKSNNYATY),

CDR-H3 comprises the amino acid sequence as set forth in SEQ ID NO: 3(HPNYSGFNYPFAS),

CDR-L1 comprises the amino acid sequence as set forth in SEQ ID NO: 4(RSSQSIVHSNGKTYFE),

CDR-L2 comprises the amino acid sequence as set forth in SEQ ID NO: 5(KVSNRFS), and

CDR-L3 comprises the amino acid sequence as set forth in SEQ ID NO: 6(FQGSHVPYT).

According to some embodiments, said CDR-H1 of the antibody orantigen-binding portion thereof comprises or consists of the amino acidsequence as set forth in SEQ ID NO: 22 (GFSFNIYAMN).

According to some embodiments, said CDR-H2 of the antibody orantigen-binding portion thereof comprises or consists of the amino acidsequence as set forth in SEQ ID NO: 23 (RIRSKSNNYATYYADSVKD).

According to some embodiments, said antibody or antigen-binding portionthereof comprises a variable region heavy chain comprising the aminoacid sequence of SEQ ID NO: 7. According to some embodiments, saidantibody or antigen-binding portion thereof comprises a constant regionheavy chain comprising the amino acid sequence of SEQ ID NO: 9.

According to some embodiments, said antibody or antigen-binding portionthereof comprises a variable region light chain comprising the aminoacid sequence of SEQ ID NO: 8. According to some embodiments, saidantibody or antigen-binding portion thereof comprises a constant regionlight chain comprising the amino acid sequence of SEQ ID NO: 10.

According to another aspect, the present invention provides an antibodyor an antigen-binding portion thereof comprising three heavy chain CDRs(CDR-H) and three light chain CDRs (CDR-L), wherein:

CDR-H1 comprises the amino acid sequences selected from SEQ ID NO: 11(VYAFSS) or SEQ ID NO: 24 (SSWMN),

CDR-H2 comprises the amino acid sequence as set forth in SEQ ID NO: 12(RIYPADGDTN),

CDR-H3 comprises the amino acid sequence as set forth in SEQ ID NO: 13(WLRAMDY),

CDR-L1 comprises the amino acid sequence as set forth in SEQ ID NO: 14(KASQNVGTNVA),

CDR-L2 comprises the amino acid sequence as set forth in SEQ ID NO: 15(SASYRYS), and

CDR-L3 comprises the amino acid sequence as set forth in SEQ ID NO: 16(QQYNSYPYT).

According to some embodiments, said CDR-H1 of the antibody orantigen-binding portion thereof comprises or consists of the amino acidsequence as set forth in SEQ ID NO: 25 (VYAFSSSWMN).

According to some embodiments, said CDR-H2 of the antibody orantigen-binding portion thereof comprises or consists of the amino acidsequence as set forth in SEQ ID NO: 26 (RIYPADGDTNYNGNFRG).

According to some embodiments, said antibody or antigen-binding portionthereof comprises a variable region heavy chain comprising the aminoacid sequence of SEQ ID NO: 17. According to some embodiments, saidantibody or antigen-binding portion thereof comprises a constant regionheavy chain comprising the amino acid sequence of SEQ ID NO: 19.

According to some embodiments, said antibody or antigen-binding portionthereof comprises a variable region light chain comprising the aminoacid sequence of SEQ ID NO: 18. According to some embodiments, saidantibody or antigen-binding portion thereof comprises a constant regionlight chain comprising the amino acid sequence of SEQ ID NO: 20.

In one embodiment, the antibody or an antigen-binding portion thereof isselected from the group consisting of a Fv, Fab, F(ab′)₂, scFV or ascFV₂ fragment.

In one embodiment, the antibody or antigen-binding portion thereof hasincreased binding affinity to PCNA. In one embodiment, the antibody orantigen-binding portion thereof has the ability to block the interactionbetween PCNA and NKp44-1.

According to another aspect, the present invention provides apharmaceutical composition comprising the antibody, or anantigen-binding portion thereof, and a pharmaceutically acceptablecarrier.

According to another aspect, the present invention provides apharmaceutical composition comprising the antibody, or anantigen-binding portion thereof, and a pharmaceutically acceptablecarrier, for use in treating an ITIM-associated disease, or anNKp44-1-associated disease or disorder, including but not limited tocancer.

According to another aspect, the present invention provides a method fortreating a subject suffering from a ITIM-associated disease, includingbut not limited to cancer, the method comprising administering to saidsubject a pharmaceutical composition comprising a therapeuticallyeffective amount of the antibody or an antigen-binding portion thereofof the present invention.

According to another aspect, the present invention provides a method fortreating a subject suffering from a NKp44-1-associated disease,including but not limited to cancer, the method comprising administeringto said subject a pharmaceutical composition comprising atherapeutically effective amount of the antibody or an antigen-bindingportion thereof of the present invention.

In some embodiments, the method comprises the step of contacting thesample with an anti-membrane-associated PCNA antibody, and detectingbinding of the antibody to membrane-associated PCNA. In someembodiments, increased levels of membrane-associated PCNA, is indicativeof an NKp44-1-associated disease or severity thereof.

According to another aspect, the current invention provides a method ofdetecting non-nuclear PCNA (e.g., membrane-associated PCNA) in asubject, comprising detecting the levels of PCNA in a sample of anon-nuclear fraction derived from the subject, such as by contacting thenon-nuclear fraction sample with an anti-PCNA antibody and detecting thebinding between the non-nuclear PCNA and the antibody.

According to another aspect, the present invention provides method ofdiagnosing, prognosticating or determining the suitability for treatmentof a subject afflicted with a NKp44-1-associated disease (e.g., cancer),comprising detecting whether PCNA is present in a sample derived fromthe subject, such as by contacting the sample with an anti-PCNA antibodyand detecting binding between the non-nuclear PCNA and the antibody,wherein the presence of PCNA in the sample is indicative of aNKp44-1-associated disease in the subject.

In some embodiments, the sample comprises a non-nuclear fraction. Insome embodiments, the anti-PCNA antibody has increased binding affinityto non-nuclear PCNA.

In some embodiments, the NKp44-1-associated disease is cancer. In someembodiments, the cancer is selected from: prostate cancer, leukemia,kidney cancer, head and neck cancer, tongue cancer, and breast cancer.

According to another aspect, the current invention provides a kit fordetecting non-nuclear PCNA, comprising an antibody or antigen bindingportion thereof.

Other features and advantages of the present invention will becomeapparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C. Over-expression of single NKp44 splice variant in NK92 cellline leads to a different function. NK92 cells were transduced withNKp44/NCR2 isoforms to overexpress isoform 1, 2 and 3 (NK92-44-1,NK92-44-2, and NK92-44-3, respectively). (A) Relative IFNγ secretion byNK92-44-1, NK92-44-2, NK92-44-3 cell lines following 18 h incubationwith HeLa GFP and HeLa GFP PCNA. (B) Example for relative quantificationof immune synapse specific F-actin accumulation. Effector NK cells wereco-incubated on confocal chamber slides with CFSE-labeled target HeLacells, fixed and permeabilized, and stained with Phalloidin and DAPI.Representative image of NK effector-HeLa target interaction is shown(left panel); For image analysis (right panel), background fluorescencenoise was eliminated using ImageJ mean threshold algorithm. In order toneglect florescent signal originated from target cell F-actin andvariation in staining intensity; gated synapse F-actin MFI was dividedby total conjugation MFI. (C) Analysis of synapse images of wildtype(wt) NK92, NK92-44-1, -2, and -3 cell lines co-incubated withCFSE-labeled target HeLa cells (n=30-40 images/group); images withover-saturated pixels were excluded from analysis. Representative imagesare below the histogram bars.

FIGS. 2A-2D. Expression of NKp44 splice variants and function of primaryperipheral NK cells following culture with IL-2 or with IL-15. Primaryhuman NK cells were isolated from blood and cultured for 6 days in thepresence of IL-2 or IL-15. (A) Flow-cytometry based analysis of CD16 andNKp44 expression at day 0 and day 6 for CD3⁻/CD56⁺ gated cells. (B) qPCRanalysis of NKp44 splice variants expression in primary NK cells at day0 and following 6 days of treatment with IL-2 or with IL-15. Function of6 days IL-2 (C)- or IL-15 (D)-cultured primary human NK cells; lysis ofHeLa GFP PCNA cells compared to lysis of HeLa GFP cells with or w/oblocking with anti NKp44 (p44-8 mAb). Bars, ±SD. *, p<0.05; **, p<0.01;***, p<0.001; Unpaired t-test, two-tail.

FIGS. 3A-3F. Poor survival of NKp44-1 profile in acute myelocyticleukemia (AML) patients. RNA-seq analysis of bone marrow samplesobtained from AML patients (TCGA data): (A) Proportions of NKp46⁺NKp44⁺(n=51) and NKp46⁺NKp44⁻ (n=115) patients from all NKp46⁺ AML cases. (B)Survival of NKp46⁺NKp44⁺ (n=36) and NKp46⁺NKp44⁻ (n=60) patients havingthe “day of death” information recoded in the TCGA data; difference isnot statistically significant. (C) Relative distribution of NKp44 splicevariants in NKp46⁺NKp44⁺ (n=51) AML cases. (D) Percentages of NKp44splice variant profiles from total NKp46⁺NKp44⁺ (n=51) AML cases. (E)Survival of NKp46⁺ AML cases with a profile of NKp44-1 (n=24) vs.NKp44-2/3 (n=12) vs. NKp44⁻ (n=60). (F) Survival of NKp46⁺ AML caseswith differential profile of NKp44-1: NKp44-1^(high) (n=12) vs.NKp44-1^(low) (n=12). NKp44-2/3 (n=12) vs. NKp44⁻ (n=60) profiles (fromE) are re-plotted for the ease of comparison.

FIGS. 4A-4C. Anti-PCNA mAbs block tumor-mediated suppression. mAbs wereraised in our laboratory against PCNA. (A) Binding of recombinant NKp44to plate-bound recombinant PCNA in the presence of titratedconcentrations of mAb 14.25. Y-axis is % binding of NKp44 normalized toNKp44 binding w/o 14.25 (left column, 100%). IFNγ secretion by NK92-44cells activated on plated bound anti-NKp44 (B) or anti NKp30 (C) in thepresence of HeLa cells pre-coated with anti-PCNA antibodies or controlmIgG1 as noted.

FIGS. 5A-5B depict light chain agarose gel electrophoresis under theprocedures for generating the mAbs described herein. Each lane shows PCRproduct of the light chain amplified with each one of the 8 forwarddegenerate primers and the reverse primer (lanes 1-8).

FIGS. 6A-6C. (A) Schematic representation of immunization schedule inmice for hybridoma production (B) Screening strategies for selection ofspecific monoclonal antibody producing clone. (C) ELISA resultrepresenting inhibition of NKp44 receptor binding to MBP-PCNA by cellculture soup of selected clones as well as membrane PCNA staining byFACS.

FIGS. 7A-7C. (A) Western blot result confirming the specific recognitionof recombinant PCNA by 14-25-9. (B) ELISA result representing binding ofFPLC purified monoclonal antibody 14-25-9 with MBP-PCNA, His-PCNA andunrelated protein His-DJ1, IgG1 is Isotype control. (C) ELISA resultshowing dose dependant inhibition of NKp44 receptor binding to PCNA by14-25-9 as well as comparison with commercial anti PCNA mAb clone PC10.

FIGS. 8A-8B. (A) Recognition of cellular PCNA from three different celllines by 14-25-9 and PC10, represented via Western blot. (B) Affinity ofpurified 14-25-9 for PCNA, measured using ProteOn. Concentrations: 0-80nM.

FIG. 9 is FACS staining showing membrane express PCNA recognition bypurified 14-25-9 in live K562 cell line compared to commercial PC10clone.

FIGS. 10A-10B presents image stream results (from HeLa cells) showingrecognition of (A) mainly cytoplasmic PCNA by 14-25-9, whereas (B) PC10binds with nuclear PCNA.

FIGS. 11A-11B is fluorescent immunohistochemistry micrographs of humanformalin fixed normal and tumor tissues; paraffin embedded biopsysamples of (A) tongue and (B) head & neck with 14-25-9 and PC10.

FIGS. 12A-12B is fluorescent immunohistochemistry micrographs of humanformalin fixed normal and tumor tissues; paraffin embedded biopsysamples of (A) kidney and (B) breast with 14-25-9 and PC10.

FIGS. 13A-13B includes graphs showing human NK activation by the 14-25-9mAb. (A) Freshly isolated human NK cells were co-incubation of withdifferent cancer cell lines from a solid tumor and from leukemiaover-night (HeLa, DU145, 721.221 and K562) in the presence of 14-25-9 orIgG1 as control. NK cells that were incubated with 14-25-9 showedincreased in IFN-γ release compared to mouse IgG1 as control. (B) AntiPCNA mAb 14-25-9 improved the lysis activity of fresh primary human NKcells when interacted with 721.221 CW6 in effector and target ratio of1:3.

FIG. 14 is a non-limiting experimental scheme of in-vivo human NKactivation against xenografts in Nude mice. (Left) Check biopsy/resectedtumor normalized expression (RNA) of NCR2 splice variant I (normalizedto immune part within the biopsy)+Staining of FFPE cut for membranelocalization of PCNA with the same mAb used for the treatment. (Right)Patient derived xenograft (PDX): Intratumoral injection of 2×10⁶patient's autologous NK (CD56 positive selection) cells grown in vitrowith IL-2 into mice. In same anesthesia tail vein injection of 14-25-9mAb (10 mg/Kg) or mock. Six (6) hr later excise tumor and: Part oftumor: freeze for RNA (qRTPCR of hiNg and NKp44 splice variants; anotherpart of tumor: digest in MACS dissociator and stain single cells formemb PCNA on tumor cells, and memb hCD107a on NK.

FIG. 15 is FACS staining of NK cells which were isolated from apatient's PBMC and propagated with IL-2. Staining with anti-human CD56(left panel) showed the expected phenotype of NK cells expressing eithermoderate or high CD56 levels. Both NK cell types were positive for NKp44expression (right panel). X axis—FL6-A MFI, base-10 log scale.

FIG. 16 is a FACS staining of human NK cells from harvested andsolubilized patient derived xenografts stained the membrane expressionof human CD107a. X axis—FL2-A MFI. Y axis—FL6-A-MFI. Both axes are inbase-10 log scale.

FIG. 17 is vertical bar charts comparisons of CD107a (NK Activationmarker) comparing pairs of PDX bearing mice injected intra-PDX withautologous NK and treated IV with 14-25-9 or control treated mice.

FIGS. 18A-18C includes (A) Western-blot result confirmed the specificrecognition of recombinant PCNA by 13-10-1 (left panel). Recognition ofcellular PCNA from three different cell lines by 14-25-9 and PC10 wasalso documented by western-blot (right panel). (B) A copy of the resultsshown in FIG. 4, with the addition from the same experiment of stainingwith 13-10-1. (C) Immunohistochemistry of human formalin fixed; paraffinembedded biopsy samples of oral cancer with 13-10-1 and PC10.

FIG. 19 is ProteOn array showing affinity of purified 13-10-1 for PCNA.Obtained values were: ka=1.10E⁺⁴ (msec⁻¹); kd=9.90E⁻⁵ (sec⁻¹);KD=8.99E⁻⁹ M; Concentrations: 0-80 nM.

DETAILED DESCRIPTION OF THE INVENTION

In some embodiments, the present invention is directed to an antibody oran antibody fragment thereof having increased binding affinity to PCNA,and the ability to block the interaction of PCNA and NKp44 isoform 1.

In some embodiments, the present invention is directed to an antibody oran antibody fragment thereof having increased binding affinity to PCNA,and the ability to block the interaction of PCNA and ITIM positiveNKp44.

In some embodiment, NKp44 is isoform-1 NKp44 (or interchangeably“natural cytotoxicity triggering receptor 2” or “NCR2”) having thepolypeptide sequence as set forth in SEQ ID NO: 35(MAWRALHPLLLLLLLFPGSQAQSKAQVLQSVAGQTLTVRCQYPPTGSLYEKKGWCKEASALVCIRLVTSSKPRTMAWTSRFTIWDDPDAGFFTVTMTDLREEDSGHYWCRIYRPSDNSVSKSVRFYLVVSPASASTQTSWTPRDLVSSQTQTQSCVPPTAGARQAPESPSTIPVPSQPQNSTLRPGPAAPIALVPVFCGLLVAKSLVLSALLVWWGDIWWKTMMELRSLDTQKATCHLQQVTDLPWTSVSSPVEREILYHTVARTKISDD DDEHTL).

The present invention, in some embodiments, is directed to an isolatedantibody or an isolated antibody fragment thereof having increasedbinding affinity to PCNA specifically, membrane-associated PCNA.

As used herein, the term “membrane-associated PCNA” refers tonon-nuclear PCNA. In some embodiments, the methods, kits andcompositions of the invention, provide anti-membrane-associated PCNAantibodies having no, or minimum affinity to nuclear PCNA.

In one embodiment, the antibody or antigen-binding portion thereof hasthe ability to block the interaction of PCNA and NKp44 isoform 1. In oneembodiment, the antibody or antigen-binding portion thereof has minimaleffect on the interaction between PCNA and any one of NKp44 isoform 2and/or NKp44 isoform 3.

In one embodiment, the antibody or antigen-binding portion thereofsubstantially blocks NKp44-PCNA interaction.

In one embodiment, the antibody or antigen-binding portion thereofsubstantially enhances NK activity, such as following exposure to tumorcells.

The present invention is based in part on the finding of novelantibodies which block NKp44-PCNA interaction. As the antibodiesdisclosed herein have increased specificity to blocking interaction withNKp44 isoform 1 (i.e., ITIM positive), the disclosed antibodies orfragments thereof may be used for treating diseases associated withNKp44 ITIM+(positive), such as cancer.

As described herein, the anti-PCNA antibodies of the invention can beused as a diagnostic and/or a prognosis agent for diseases or conditionswherein the NKp44 isoform 1 expression or activity is involved, such ascancer and specifically AML, as demonstrated herein.

An “anti-PCNA antibody”, “an antibody which recognizes PCNA”, or “anantibody against PCNA” is an antibody that binds to PCNA, withsufficient affinity and specificity. In some embodiments, an anti-PCNAantibody as disclosed herein has neutralizing activity over PCNA.

In some embodiments, antibody or antigen-binding portion thereof of thepresent invention, preferably binds to non-nuclear PCNA than to nuclearPCNA. As a non-limiting example, antibody or antigen-binding portionthereof of the present invention, as used herein “13-10-1” and “14-25-9”bind to non-nuclear PCNA with KD values of 8.99E⁻⁹ M and 3.54E⁻⁸ M,respectively.

As used herein, the terms “increased binding affinity” and “greaterbinding affinity” are interchangeable. In some embodiments, antibody orantigen-binding portion thereof of the present invention has a greaterbinding affinity to the non-nuclear PCNA compared to the nuclear PCNA.In one embodiment, greater affinity as used herein is by 10%. In oneembodiment, greater affinity as used herein is by 30%. In oneembodiment, greater affinity as used herein is by 50%. In oneembodiment, greater affinity as used herein is by 75%. In oneembodiment, greater affinity as used herein is by 100%. In oneembodiment, greater affinity as used herein is by 150%. In oneembodiment, greater affinity as used herein is by 250%. In oneembodiment, greater affinity as used herein is by 500%. In oneembodiment, greater affinity as used herein is by 1,000%. In oneembodiment, greater affinity as used herein is by 1.5-fold. In oneembodiment, greater affinity as used herein is by 2-fold. In oneembodiment, greater affinity as used herein is by 5-fold. In oneembodiment, greater affinity as used herein is by 10-fold. In oneembodiment, greater affinity as used herein is by 50-fold. In oneembodiment, greater affinity as used herein is by 100-fold. In oneembodiment, greater affinity as used herein is by 500-fold. In oneembodiment, greater affinity as used herein is by 1,000-fold.

The term “antibody” (also referred to as an “immunoglobulin”) is used inthe broadest sense and specifically encompasses monoclonal antibodiesand antibody fragments so long as they exhibit the desired biologicalactivity. In certain embodiments, the use of a chimeric antibody or ahumanized antibody is also encompassed by the invention.

The basic unit of the naturally occurring antibody structure is aheterotetrameric glycoprotein complex of about 150,000 daltons, composedof two identical light (L) chains and two identical heavy (H) chains,linked together by both noncovalent associations and by disulfide bonds.Each heavy and light chain also has regularly spaced intra-chaindisulfide bridges. Five human antibody classes (IgG, IgA, IgM, IgD andIgE) exist, and within these classes, various subclasses, are recognizedbased on structural differences, such as the number of immunoglobulinunits in a single antibody molecule, the disulfide bridge structure ofthe individual units, and differences in chain length and sequence. Theclass and subclass of an antibody is its isotype.

The amino terminal regions of the heavy and light chains are morediverse in sequence than the carboxy terminal regions, and hence aretermed the variable domains. This part of the antibody structure confersthe antigen-binding specificity of the antibody. A heavy variable (VH)domain and a light variable (VL) domain together form a singleantigen-binding site, thus, the basic immunoglobulin unit has twoantigen-binding sites. Particular amino acid residues are believed toform an interface between the light and heavy chain variable domains(Chothia et al., J. Mol. Biol. 186, 651-63 (1985); Novotny and Haber,(1985) Proc. Natl. Acad. Sci. USA 82 4592-4596).

The carboxy terminal portion of the heavy and light chains form theconstant domains i.e. CH1, CH2, CH3, CL. While there is much lessdiversity in these domains, there are differences from one animalspecies to another, and further, within the same individual there areseveral different isotypes of antibody, each having a differentfunction.

The term “framework region” or “FR” refers to the amino acid residues inthe variable domain of an antibody, which are other than thehypervariable region amino acid residues as herein defined. The term“hypervariable region” as used herein refers to the amino acid residuesin the variable domain of an antibody, which are responsible for antigenbinding. The hypervariable region comprises amino acid residues from a“complementarity determining region” or “CDR”. The CDRs are primarilyresponsible for binding to an epitope of an antigen. The extent of FRsand CDRs has been precisely defined (see, Kabat et al.).

Immunoglobulin variable domains can also be analyzed using the IMGTinformation system (www://imgt. cines.fr/) (IMGT®/V-Quest) to identifyvariable region segments, including CDRs. See, e.g., Brochet, X. et al,Nucl. Acids Res. J6:W503-508 (2008).

Kabat et al. also defined a numbering system for variable domainsequences that is applicable to any antibody. One of ordinary skill inthe art can unambiguously assign this system of “Kabat numbering” to anyvariable domain sequence, without reliance on any experimental databeyond the sequence itself. As used herein, “Kabat numbering” refers tothe numbering system set forth by Kabat et al, U.S. Dept. of Health andHuman Services, “Sequence of Proteins of Immunological Interest” (1983).

TABLE 1  The amino acid sequences of the CDR sequences ofthe antibodies of the invention. mAb mAb #1 (SEQ ID NO)mAb #2 (SEQ ID NO) CDR H1 (AbM) GFSFNIYAMN (22) VYAFSSSWMN (25) CDR H1 GFSFNI (1) VYAFSS (11) (Chothia) CDR H1 (Kabat) IYAMN (21) SSWMN (24)CDR H2 (AbM RIRSKSNNYATY (2) RIYPADGDTN (12) and Chothia) CDR H2 RIRSKSNNYATYYADS RIYPADGDTNYNGNFRG (Kabat) VKD (23) (26) CDR H3HPNYSGFNYPFAS (3) WLRANIDY (13) CDR L1 RSSQSIVHSNGKTYFE KASQNVGTNVA (14) (4) CDR L2 KVSNRFS (5) SASYRYS (15) CDR L3FQGSHVPYT (6) QQYNSYPYT (16)

An “antigen” is a molecule or a portion of a molecule capable ofeliciting antibody formation and being bound by an antibody. An antigenmay have one or more than one epitope. The specific reaction referred toabove is meant to indicate that the antigen will react, in a highlyselective manner, with its corresponding antibody and not with themultitude of other antibodies which may be evoked by other antigens.

The term “antigenic determinant” or “epitope” according to the inventionrefers to the region of an antigen molecule that specifically reactswith particular antibody. Peptide sequences derived from an epitope canbe used, alone or in conjunction with a carrier moiety, applying methodsknown in the art, to immunize animals and to produce additionalpolyclonal or monoclonal antibodies.

The monoclonal antibodies herein specifically include “chimeric”antibodies in which a portion of the heavy and/or light chain isidentical with or homologous to corresponding sequences in antibodiesderived from a particular species or belonging to a particular antibodyclass or subclass, while the remainder of the chain(s) is identical withor homologous to corresponding sequences in antibodies derived fromanother species or belonging to another antibody class or subclass, aswell as fragments of such antibodies, so long as they exhibit thedesired biological activity (U.S. Pat. No. 4,816,567; and Morrison etal, Proc. Natl. Acad. Sci. USA 57:6851-6855 (1984)). In addition,complementarity determining region (CDR) grafting may be performed toalter certain properties of the antibody molecule including affinity orspecificity. A non-limiting example of CDR grafting is disclosed in U.S.Pat. No. 5,225,539.

Chimeric antibodies are molecules, the different portions of which arederived from different animal species, such as those having a variableregion derived from a murine mAb and a human immunoglobulin constantregion. Antibodies which have variable region framework residuessubstantially from human antibody (termed an acceptor antibody) andcomplementarity determining regions substantially from a mouse antibody(termed a donor antibody) are also referred to as humanized antibodies.Chimeric antibodies are primarily used to reduce immunogenicity inapplication and to increase yields in production, for example, wheremurine mAbs have higher yields from hybridomas but higher immunogenicityin humans, such that human/murine chimeric mAbs are used. Chimericantibodies and methods for their production are known in the art (forexample PCT patent applications WO 86/01533, WO 97/02671, WO 90/07861,WO 92/22653 and U.S. Pat. Nos. 5,693,762, 5,693,761, 5,585,089,5,530,101 and 5,225,539). As used herein, the term “humanized antibody”refers to an antibody comprising a framework region from a humanantibody and one or more CDRs from a non-human (usually a mouse or rat)immunoglobulin. Parts of a humanized immunoglobulin, except possibly theCDRs, are substantially identical to corresponding parts of naturalhuman immunoglobulin sequences. In some cases, however, specific aminoacid residues, for example in the framework regions, may be modified, soas to optimize performance of the humanized antibody. Importantly, thehumanized antibody is expected to bind to the same antigen as the donorantibody that provides the CDRs. For further details, see e.g. U.S. Pat.No. 5,225,539 assigned to Medical Research Council, UK. The terms “aframework region from an acceptor human immunoglobulin” and “a frameworkregion derived from an acceptor human immunoglobulin”, and similargrammatical expressions are used interchangeably herein to refer to aframework region or portion thereof that has the same amino acidsequence of the acceptor human immunoglobulin.

As used herein, the terms “CAR-T cell” and “CAR-NK cell” refer to anengineered receptor which has specificity for at least one protein ofinterest (for example an immunogenic protein with increased expressionfollowing treatment with an epigenetic modifying agent) and is graftedonto an immune effector cell (a T cell or NK cell). In some embodiments,the CAR-T cell has the specificity of a monoclonal antibody grafted ontoa T-cell. In some embodiments, the CAR-NK cell has the specificity of amonoclonal antibody grafted onto a NK-cell. In some embodiments, the Tcell is selected from a cytotoxic T lymphocyte and a regulatory T cell.

CAR-T and CAR-NK cells and their vectors are well known in the art. Suchcells target and are cytotoxic to the protein for which the receptorbinds. In some embodiments, a CAR-T or CAR-NK cell targets at least oneviral protein. In some embodiments, a CAR-T or CAR-NK cell targets aplurality of viral proteins. In some embodiments, a CAR-T or CAR-NK celltargets a viral protein with increased expression due to contact with anepigenetic modifying agent.

Construction of CAR-T cells is well known in the art. In onenon-limiting example, a monoclonal antibody to a viral protein can bemade and then a vector coding for the antibody will be constructed. Thevector will also comprise a costimulatory signal region. In someembodiments, the costimulatory signal region comprises the intracellulardomain of a known T cell or NK cell stimulatory molecule. In someembodiments, the intracellular domain is selected from at least one ofthe following: CD3Z, CD27, CD28, 4-1BB, OX40, CD30, CD40, PD-1, ICOS,lymphocyte function-associated antigen-1 (LFA-1), CD2, CD 7, LIGHT,NKG2C, B7-H3, and a ligand that specifically binds with CD83. In someembodiments, the vector also comprises a CD3Z signaling domain. Thisvector is then transfected, for example by lentiviral infection, into aT-cell.

As used herein, the term “immunotherapeutic agent” refers to anymolecule, compound, solution or cell that elicits an active immuneresponse. In some embodiments, the immunotherapeutic agent activates theimmune system. In some embodiments, the immunotherapeutic agent is acancer-targeting immunotherapeutic agent. In some embodiments, theimmunotherapeutic agent elicits an active immune response against acancer or cell thereof. In some embodiments, the immunotherapeutic agentelicits a general immune response. In some embodiments, theimmunotherapeutic agent elicits an immune response against a specificprotein, group of proteins, transcript or group of transcripts. Eachpossibility represents a separate embodiment of the invention. An immunecheckpoint inhibitor would be a non-limiting example of animmunotherapeutic agent that elicits a general immune response. Achimeric antigen receptor CAR-T cell, CAR-NK cell or a cytotoxicmonoclonal antibody would be non-limiting examples of immunotherapeuticagents that elicit a response against a specific protein. A vaccinewould be a non-limiting example of an immunotherapeutic agent thatelicit a response against a group of proteins or transcripts (or even asingular protein or transcript). In some embodiments, theimmunotherapeutic agent is selected from: a CAR-T cell, a vaccine, anantibody and an immune checkpoint inhibitor. In some embodiments, theimmunotherapeutic agent is a CAR-T cell, a vaccine, a cytotoxic antibodyor an immune checkpoint inhibitor. Each possibility represents aseparate embodiment of the invention.

In some embodiments, the immunotherapeutic agent binds to theimmunogenic protein. In some embodiments, the immunotherapeutic agentbinds to the increased immunogenic protein. In such embodiments, theimmunotherapeutic agent is an agent that targets a specific protein orproteins. In such embodiments, the immunotherapeutic agent is selectedfrom a CAR-T cell, a CAR-NK cell, a vaccine, and a cytotoxic monoclonalantibody. In some embodiments, the virus is an endogenous virus and theimmunotherapeutic agent directly binds to the increased immunogenicprotein.

The term “monoclonal antibody” or “mAb” as used herein refers to anantibody obtained from a population of substantially homogeneousantibodies, i.e., the individual antibodies comprising the populationare identical and/or bind the same epitope, except for possible variantsthat may arise during production of the monoclonal antibody, suchvariants generally being present in minor amounts. In contrast topolyclonal antibody preparations that typically include differentantibodies directed against different determinants (epitopes), eachmonoclonal antibody is directed against a single determinant on theantigen. In addition to their specificity, the monoclonal antibodies areadvantageous in that they are uncontaminated by other immunoglobulins.The modifier “monoclonal” indicates the character of the antibody asbeing obtained from a substantially homogeneous population ofantibodies, and is not to be construed antibodies to be used inaccordance with the methods provided herein may be made by the hybridomamethod first described by Kohler et al, Nature 256:495 (1975), or may bemade by recombinant DNA methods (see, e.g., U.S. Pat. No. 4,816,567).The “monoclonal antibodies” may also be isolated from phage antibodylibraries using the techniques described in Clackson et al, Nature352:624-628 (1991) and Marks et al, J. Mol. Biol. 222:581-597 (1991),for example.

The mAb of the present invention may be of any immunoglobulin classincluding IgG, IgM, IgD, IgE or IgA. A hybridoma producing a mAb may becultivated in vitro or in vivo. High titers of mAbs can be obtained invivo production where cells from the individual hybridomas are injectedintraperitoneally into pristine-primed Balb/c mice to produce ascitesfluid containing high concentrations of the desired mAbs. mAbs ofisotype IgM or IgG may be purified from such ascites fluids, or fromculture supernatants, using column chromatography methods well known tothose of skill in the art.

“Antibody fragments” comprise a portion of an intact antibody,preferably comprising the antigen binding region thereof. Examples ofantibody fragments include Fab, Fab′, F(ab′)2, and Fv fragments;diabodies; tandem diabodies (taDb), linear antibodies (e.g., U.S. Pat.No. 5,641,870, Example 2; Zapata et al, Protein Eng. 8(10): 1057-1062(1995)); one-armed antibodies, single variable domain antibodies,minibodies, single-chain antibody molecules; multispecific antibodiesformed from antibody fragments (e.g., including but not limited to,Db-Fc, taDb-Fc, taDb-CH3, (scFV)4-Fc, di-scFv, bi-scFv, or tandem(di,tri)-scFv); and Bi-specific T-cell engagers (BiTEs).

Papain digestion of antibodies produces two identical antigen-bindingfragments, called “Fab” fragments, each with a single antigen-bindingsite, and a residual “Fc” fragment, whose name reflects its ability tocrystallize readily. Pepsin treatment yields an F(ab′)₂ fragment thathas two antigen-binding sites and is still capable of cross-linkingantigen.

“Fv” is the minimum antibody fragment that contains a completeantigen-recognition and antigen-binding site. This region consists of adimer of one heavy chain and one light chain variable domain in tight,non-covalent association. It is in this configuration that the threesurfaces of the VH-VL dimer. Collectively, the six hypervariable regionsconfer antigen-binding specificity to the antibody. However, even asingle variable domain (or half of an Fv comprising only threehypervariable regions specific for an antigen) has the ability torecognize and bind antigen, although at a lower affinity than the entirebinding site.

The Fab fragment also contains the constant domain of the light chainand the first constant domain (CHI) of the heavy chain. Fab′ fragmentsdiffer from Fab fragments by the addition of a few residues at thecarboxy terminus of the heavy chain CHI domain including one or morecysteines from the antibody hinge region. Fab′-SH is the designationherein for Fab′ in which the cysteine residue(s) of the constant domainsbear at least one free thiol group. F(ab′)2 antibody fragmentsoriginally were produced as pairs of Fab′ fragments that have hingecysteines between them. Other chemical couplings of antibody fragmentsare also known.

The “light chains” of antibodies (immunoglobulins) from any vertebratespecies can be assigned to one of two clearly distinct types, calledkappa and lambda, based on the amino acid sequences of their constantdomains.

Depending on the amino acid sequence of the constant domain of theirheavy chains, antibodies can be assigned to different classes. There arefive major classes of intact antibodies: IgA, IgD, IgE, IgG, and IgM,and several of these may be further divided into subclasses (isotypes),e.g., IgG1, IgG2, IgG3, IgG4, IgA, and IgA2. The heavy chain constantdomains that correspond to the different classes of antibodies arecalled a, delta, e, gamma, and micro, respectively. The subunitstructures and three-dimensional configurations of different classes ofimmunoglobulins are well known.

“Single-chain Fv” or “scFv” antibody fragments comprise the VH and VLdomains of antibody, wherein these domains are present in a singlepolypeptide chain. In some embodiments, the Fv polypeptide furthercomprises a polypeptide linker between the VH and VL domains thatenables the scFv to form the desired structure for antigen binding. Fora review of scFv see Pluckthun in The Pharmacology of MonoclonalAntibodies, vol. 113, Rosenburg and Moore eds., Springer-Verlag, NewYork, pp. 269-315 (1994).

The term “diabodies” refers to small antibody fragments with twoantigen-binding sites, which fragments comprise a heavy chain variabledomain (VH) connected to a light chain variable domain (VL) in the samepolypeptide chain (VH-VL). By using a linker that is too short to allowpairing between the two domains on the same chain, the domains areforced to pair with the complementary domains of another chain andcreate two antigen-binding sites. Diabodies are Natl. Acad. Sci. USA,90:6444-6448 (1993).

The term “multispecific antibody” is used in the broadest sense andspecifically covers an antibody that has polyepitopic specificity. Suchmultispecific antibodies include, but are not limited to, an antibodycomprising a heavy chain variable domain (VH) and a light chain variabledomain (VL), where the VHVL unit has polyepitopic specificity,antibodies having two or more VL and VH domains with each VHVL unitbinding to a different epitope, antibodies having two or more singlevariable domains with each single variable domain binding to a differentepitope, full length antibodies, antibody fragments such as Fab, Fv,dsFv, scFv, diabodies, bispecific diabodies, triabodies, tri-functionalantibodies, antibody fragments that have been linked covalently ornon-covalently. “Polyepitopic specificity” refers to the ability tospecifically bind to two or more different epitopes on the same ordifferent target(s).

The monoclonal antibodies of the invention may be prepared using methodswell known in the art. Examples include various techniques, such asthose in Kohler, G. and Milstein, C, Nature 256: 495-497 (1975); Kozboret al, Immunology Today 4: 72 (1983); Cole et al, pg. 77-96 inMONOCLONAL ANTIBODIES AND CANCER THERAPY, Alan R. Liss, Inc. (1985).

Besides the conventional method of raising antibodies in vivo,antibodies can be generated in vitro using phage display technology.Such a production of recombinant antibodies is much faster compared toconventional antibody production and they can be generated against anenormous number of antigens. Furthermore, when using the conventionalmethod, many antigens prove to be non-immunogenic or extremely toxic,and therefore cannot be used to generate antibodies in animals.Moreover, affinity maturation (i.e., increasing the affinity andspecificity) of recombinant antibodies is very simple and relativelyfast. Finally, large numbers of different antibodies against a specificantigen can be generated in one selection procedure. To generaterecombinant monoclonal antibodies, one can use various methods all basedon display libraries to generate a large pool of antibodies withdifferent antigen recognition sites. Such a library can be made inseveral ways: One can generate a synthetic repertoire by cloningsynthetic CDR3 regions in a pool of heavy chain germline genes and thusgenerating a large antibody repertoire, from which recombinant antibodyfragments with various specificities can be selected. One can use thelymphocyte pool of humans as starting material for the construction ofan antibody library. It is possible to construct naive repertoires ofhuman IgM antibodies and thus create a human library of large diversity.This method has been widely used successfully to select a large numberof antibodies against different antigens. Protocols for bacteriophagelibrary construction and selection of recombinant antibodies areprovided in the well-known reference text Current Protocols inImmunology, Colligan et al (Eds.), John Wiley & Sons, Inc. (1992-2000),Chapter 17, Section 17.1.

Non-human antibodies may be humanized by any methods known in the art.In one method, the non-human complementarity determining regions (CDRs)are inserted into a human antibody or consensus antibody frameworksequence. Further changes can then be introduced into the antibodyframework to modulate affinity or immunogenicity.

In some embodiments, antibodies as described herein are neutralizingantibodies. “Neutralization”, as discussed here, is defined as thereduction of NKp44-PCNA interaction by antibodies of the invention.

In some embodiments, neutralizing antibodies include: antibodies,fragments of antibodies, Fab and F(ab′)2, single-domain antigen-bindingrecombinant fragments and natural nanobodies.

In some embodiments, the present invention provides nucleic acidsequences encoding the antibody of the present invention.

In one embodiment, an antibody as described herein comprises a lightchain variable domain encoded by a DNA sequence comprising the followingnucleic acid sequence

(SEQ ID NO: 27): TGACATTGTGATGACTCAGTCTCAAAAAATCATGTCCACATCAGTAGGAGACAGGGTCAGCGTCACCTGCAAGGCCAGTCAGAATGTGGGTACTAATGTAGCCTGGTATCAACAGAAACCAGGGCAATCTCCTAAAGTACTGATTTACTCGGCATCCTACCGGTACAGTGGAGTCCCTGATCGCTTCACAGGCAGTGGATCTGGGACAGATTTCACTCTCAGCATCAGCAATGTGCAGTCTGAAGACTTGGCAGAGTATTTCTGTCAGCAATATAACAGCTATCCGTACACGTTCGGAGGGGGGACCAAGCTGGAAATAAAA.

In one embodiment, an antibody as described herein comprises a lightchain constant domain encoded by a DNA sequence comprising the followingnucleic acid sequence

(SEQ ID NO: 28): CGGGCTGATGCTGCACCAACTGTATCCATCTTCCCACCATCCAGTGAGCAGTTAACATCTGGAGGTGCCTCAGTCGTGTGCTTCTTGAACAACTTCTACCCCAAAGACATCAATGTCAAGTGGAAGATTGATGGCAGTGAACGACAAAATGGCGTCCTGAACAGTTGGACTGATCAGGACAGCAAAGACAGCACCTACAGCATGAGCAGCACCCTCACGTTGACCAAGGACGAGTATGAACGACATAACAGCTATACCTGTGAGGCCACTCACAAGACATCAACTTCACCCATTGTCAAGAGCTTCAACAGGAATGAGTGTTAGA.

In one embodiment, an antibody as described herein comprises a heavychain variable domain encoded by a DNA sequence comprising the followingnucleic acid sequence

(SEQ ID NO: 29): GAGCCTGGGGCCTCAGTGAAGATTTCCTGCAAGGCTTCTGTCTACGCATTCAGTAGTTCCTGGATGAACTGGGTGAAGCAGAGGCCTGGAAAGGGTCTTGAGTGGATTGGACGGATTTATCCTGCAGATGGAGATACTAACTACAATGGGAACTTCAGGGGCAAGGCCACACTGACTGCAGACAAATCCTCCAGCACAGCCTACATGCAACTCAGCAGTCTGACATCTGAGGACTCTGCGGTCTACTTCTGTGCAAGATGGTTACGGGCTATGGACTACTGGGGTCAAGGAACCTCAGTC ACCGTCTCCTCA.

In one embodiment, an antibody as described herein comprises a heavychain constant domain encoded by a DNA sequence comprising the followingnucleic acid sequence

(SEQ ID NO: 30): GCCAAAACAACATACCCCCCATCTGTCTATCCACTGGCCCCTGGATCTGCTGCCCAAACTAACTCCATGGTGACCCTGGGATGCCTGGTCAAGGGCTATTTCCCTGAGCCAGTGACAGTGACCTGGAACTCTGGATCCCTGTCCAGCGGTGTGCACACCTTCCCAGCTGTCCTGCAGTCTGACCTCTACACTCTGAGCAGCTCAGTGACTGTCCCCTCCAGCACCTGGCCCAGCGAGACCGTCACCTGCAACGTTGCCCACCCGGCCAGCAGCACCAAGGTGGACAAGAAAATTGTGCCCAGGGATTGTGGTTGTAAGCCTTGCATATGTACAGTCCCAGAAGTATCATCTGTCTTCATCTTCCCCCCAAAGCCCAAGGATGTGCTCACCATTACTCTGACTCCTAAGGTCACGTGTGTTGTGGTAGACATCAGCAAGGATGATCCCGAGGTCCAGTTCAGCTGGTTTGTAGATGATGTGGAGGTGCACACAGCTCAGACGCAACCCCGGGAGGAGCAGTTCAACAGCACTTTCCGCTCAGTCAGTGAACTTCCCATCATGCACCAGGACTGGCTCAATGGCAAGGAGTTCAAATGCAGGGTCAACAGTGCAGCTTTCCCTGCCCCCATCGAGAAAACCATCTCCAAAACCAAAGGCAGACCGAAGGCTCCACAGGTGTACACCATTCCACCTCCCAAGGAGCAGATGGCCAAGGATAAAGTCAGTCTGACCTGCATGATAACAGACTTCTTCCCTGAAGACATTACTGTGGAGTGGCAGTGGAATGGGCAGCCAGCGGAGAACTACAAGAACACTCAGCCCATCATGGACACAGATGGCTCTTACTTCGTCTACAGCAAGCTCAATGTGCAGAAGAGCAACTGGGAGGCAGGAAATACTTTCACCTGCTCTGTGTTACATGAGGGCCTGCACAACCACCATACTGAGAAGAGCCTCTCCCACTCTCCTGGTAAATGA.

In one embodiment, an antibody as described herein comprises a lightchain variable domain encoded by a DNA sequence comprising the followingnucleic acid sequence

(SEQ ID NO: 31): TGATGTTGTGATGACCCAAACTCCGCTCTCCCTGCCTGTCAGTCTTGGAGATCAAGCCTCCATCTCTTGCAGATCTAGTCAGAGCATTGTACATAGTAATGGAAAGACCTATTTTGAATGGTACCTTCAGAAACCAGGCCAGTCTCCAAAGCTCCTGATCTACAAAGTTTCCAACCGATTTTCTGGGGTCCCAGACAGGTTCAGTGGCAGTGGATCAGGGACAGAATTCACACTCAAGATCAGCAGAGTGGAGGCTGAGGATCTGGGAGTTTATTACTGCTTTCAAGGTTCACATGTTCCGTACACGTTCGGAGGGGGGACCAAGCTGGAAATAAAA.

In one embodiment, an antibody as described herein comprises a lightchain constant domain encoded by a DNA sequence comprising the followingnucleic acid sequence

(SEQ ID NO: 32): CGGGCTGATGCTGCACCAACTGTATCCATCTTCCCACCATCCAGTGAGCAGTTAACATCTGGAGGTGCCTCAGTCGTGTGCTTCTTGAACAACTTCTACCCCAAAGACATCAATGTCAAGTGGAAGATTGATGGCAGTGAACGACAAAATGGCGTCCTGAACAGTTGGACTGATCAGGACAGCAAAGACAGCACCTACAGCATGAGCAGCACCCTCACGTTGACCAAGGACGAGTATGAACGACATAACAGCTATACCTGTGAGGCCACTCACAAGACATCAACTTCACCCATTGTCAAGAGCTTCAACAGGAATGAGTGTTAG.

In one embodiment, an antibody as described herein comprises a heavychain variable domain encoded by a DNA sequence comprising the followingnucleic acid sequence

(SEQ ID NO: 33): AAGCTGGTGGAGTCTGGTGGAGGATTGGTGCAGCCTACAGGGTCATTGAAACTCTCATGTGTAACCTCTGGATTCAGTTTCAATATCTACGCCATGAACTGGGTCCGCCAGGCTCCAGGAAAGGGTTTGGAATGGGTTGCTCGCATAAGAAGTAAAAGTAATAATTATGCAACATATTATGCCGATTCAGTGAAAGACAGATTCACCATCTCCAGAGATGATTCAGAAAGCATGCTCTATCTCCAAATGAACAACTTGAAAACTGAGGACACAGCCATGTATTACTGTATGAGACACCCCAATTACTCCGGCTTTAACTACCCGTTTGCTTCCTGGGGCCCAGGGACTCT GGTCACTGTCTCTGCA.

In one embodiment, an antibody as described herein comprises a heavychain constant domain encoded by a DNA sequence comprising the followingnucleic acid sequence

(SEQ ID NO: 34): GCCAAAACGACACCCCCATCTGTCTATCCACTGGCCCCTGGATCTGCTGCCCAAACTAACTCCATGGTGACCCTGGGATGCCTGGTCAAGGGCTATTTCCCTGAGCCAGTGACAGTGACCTGGAACTCTGGATCCCTGTCCAGCGGTGTGCACACCTTCCCAGCTGTCCTGCAGTCTGACCTCTACACTCTGAGCAGCTCAGTGACTGTCCCCTCCAGCACCTGGCCCAGCCAGACCGTCACCTGCAACGTTGCCCACCCGGCCAGCAGCACCAAGGTGGACAAGAAAATTGTGCCCAGGGATTGTGGTTGTAAGCCTTGCATATGTACAGTCCCAGAAGTATCATCTGTCTTCATCTTCCCCCCAAAGCCCAAGGATGTGCTCACCATTACTCTGACTCCTAAGGTCACGTGTGTTGTGGTAGACATCAGCAAGGATGATCCCGAGGTCCAGTTCAGCTGGTTTGTAGATGATGTGGAGGTGCACACAGCTCAGACGAAACCCCGGGAGGAGCAGATCAACAGCACTTTCCGTTCAGTCAGTGAACTTCCCATCATGCACCAGGACTGGCTCAATGGCAAGGAGTTCAAATGCAGGGTCAACAGTGCAGCTTTCCCTGCCCCCATCGAGAAAACCATCTCCAAAACCAAAGGCAGACCGAAGGCTCCACAGGTGTACACCATTCCACCTCCCAAGGAGCAGATGGCCAAGGATAAAGTCAGTCTGACCTGCATGATAACAAACTTCTTCCCTGAAGACATTACTGTGGAGTGGCAGTGGAATGGGCAGCCAGCGGAGAACTACAAGAACACTCAGCCCATCATGGACACAGATGGCTCTTACTTCGTCTACAGCAAGCTCAATGTGCAGAAGAGCAACTGGGAGGCAGGAAATACTTTCACCTGCTCTGTGTTACATGAGGGCCTGCACAACCACCATACTGAGAAGAGCCTCTCCCACTCTCCTGGTAAATGA.

In one embodiment, an antibody as described herein is encoded by a DNAmolecule comprising a DNA sequence having at least 75% identity to a DNAsequence as described herein. In one embodiment, an antibody asdescribed herein is encoded by a DNA molecule comprising a DNA sequencehaving at least 80% identity to a DNA sequence as described herein. Inone embodiment, an antibody as described herein is encoded by a DNAmolecule comprising a DNA sequence having at least 85% identity to a DNAsequence as described herein. In one embodiment, an antibody asdescribed herein is encoded by a DNA molecule comprising a DNA sequencehaving at least 90% identity to a DNA sequence as described herein. Inone embodiment, an antibody as described herein is encoded by a DNAmolecule comprising a DNA sequence having at least 95% identity to a DNAsequence as described herein.

“Polynucleotide,” or “nucleic acid,” as used interchangeably herein,refer to polymers of nucleotides of any length, and include DNA and RNA.

Polynucleotides encoding polypeptides may be obtained from any sourceincluding, but not limited to, a cDNA library prepared from tissuebelieved to possess the polypeptide mRNA and to express it at adetectable level. Accordingly, polynucleotides encoding a polypeptidecan be conveniently obtained from a cDNA library prepared from humantissue. The polypeptide-encoding gene may also be obtained from agenomic library or by known synthetic procedures (e.g., automatednucleic acid synthesis).

For example, the polynucleotide may encode an entire immunoglobulinmolecule chain, such as a light chain or a heavy chain. A complete heavychain includes not only a heavy chain variable region (VH) but also aheavy chain constant region (CH), which typically will comprise threeconstant domains: CH1, CH2 and CH3; and a “hinge” region. In somesituations, the presence of a constant region is desirable.

Other polypeptides which may be encoded by the polynucleotide includeantigen-binding antibody fragments such as single domain antibodies(“dAbs”), Fv, scFv, Fab′ and CHI and CK or CL domain has been excised.As minibodies are smaller than conventional antibodies they shouldachieve better tissue penetration in clinical/diagnostic use, but beingbivalent they should retain higher binding affinity than monovalentantibody fragments, such as dAbs. Accordingly, unless the contextdictates otherwise, the term “antibody” as used herein encompasses notonly whole antibody molecules, but also antigen-binding antibodyfragments of the type discussed above. Each framework region present inthe encoded polypeptide may comprise at least one amino acidsubstitution relative to the corresponding human acceptor framework.Thus, for example, the framework regions may comprise, in total, three,four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen,fourteen, or fifteen amino acid substitutions relative to the acceptorframework regions. Given the properties of the individual amino acidscomprising the disclosed protein products, some rational substitutionswill be recognized by the skilled worker. Amino acid substitutions, i.e.“conservative substitutions,” may be made, for instance, on the basis ofsimilarity in polarity, charge, solubility, hydrophobicity,hydrophilicity, and/or the amphipathic nature of the residues involved.

Suitably, the polynucleotides described herein may be isolated and/orpurified. In some embodiments, the polynucleotides are isolatedpolynucleotides.

As used herein, the term “non-naturally occurring” substance,composition, entity, and/or any combination of substances, compositions,or entities, or any grammatical variants thereof, is a conditional termthat explicitly excludes, but only excludes, those forms of thesubstance, composition, entity, and/or any combination of substances,compositions, or entities that are well-understood by persons ofordinary skill in the art as being “naturally-occurring,” or that are,or might be at any time, determined or interpreted by a judge or anadministrative or judicial body to be, “naturally-occurring”.

Methods for Treatment and Diagnosis

As used herein the term “treatment” refers to clinical intervention inan attempt to alter the course of disease in the individual beingtreated, and can be performed either for prophylaxis or during thecourse of clinical pathology. Desirable effects of treatment includepreventing occurrence or recurrence of the disease, alleviation ofsymptoms, reducing a pathological consequence of the disease, reducingthe rate of disease progression, amelioration of the disease state,remission or improved prognosis. The term “treatment” may also encompassex vivo procedures affecting cells or tissues in culture.

As used herein the term “subject” refers to an individual, or a patient,which is a vertebrate, e.g., a mammal, including especially a human.

As defined herein, binding of an antigen molecule by an antibody resultsin blocking said antigen's activity. The term “blocking” used herein isinterchangeable with “attenuating”, “inhibiting”, “reducing” and“decreasing”.

In some embodiments of the methods described herein, blocking isreducing by more than 2%. In some embodiments of the methods describedherein, blocking is reducing by more than 5%. In some embodiments of themethods described herein, blocking is reducing by more than 10%. In someembodiments of the methods described herein, blocking is reducing bymore than 25%. In some embodiments of the methods described herein,blocking is reducing by more than 50%. In some embodiments of themethods described herein, blocking is reducing by more than 75%. In someembodiments of the methods described herein, blocking is reducing bymore than 90%. In some embodiments of the methods described herein,blocking is reducing by more than 95%. In some embodiments of themethods described herein, blocking is reducing by 99%.

As defined herein “biological sample” refers to a physical specimen fromany animal. In another embodiment, biological sample is obtained from amammal. In another embodiment, biological sample is obtained from ahuman. In another embodiment, biological sample is obtained well withinthe capabilities of those skilled in the art. The biological sampleincludes, but not limited to, biological fluids such as serum, plasma,vitreous fluid, lymph fluid, synovial fluid, follicular fluid, seminalfluid, amniotic fluid, milk, whole blood, urine, cerebrospinal fluid,saliva, sputum, tears, perspiration, mucus, and tissue culture media,including tissue extracts such as homogenized tissue, and cellularextracts. In another embodiment, a biological sample is a biopsy. Inanother embodiment, a biological sample is a resected tumor. In anotherembodiment, a biological sample includes histological sections processedas known by one skilled in the art. The terms sample and biologicalsample used herein, are interchangeable.

As defined herein, non-nuclear fraction refers to any tissue or cellextract excluding the cellular nucleus. In one embodiment, non-nuclearextract includes the cytoplasm. In one embodiment, non-nuclear extractincludes cellular organelles. In one embodiment, non-nuclear extractincludes the mitochondrion, endoplasmic reticulum, Golgi apparatus,lysosome, exosome and others. In one embodiment, non-nuclear extractincludes cellular membrane or fragments thereof. In one embodiment,non-nuclear extract includes proteins. In one embodiment, non-nuclearproteins include cytoplasm and peripheral proteins. In one embodiment,non-nuclear extract includes soluble molecules. In one embodiment,non-nuclear extract includes membrane-associated molecules. In oneembodiment, membrane associated molecules are integral, spanning or inproximity to the cellular membrane.

In some embodiments, to create a non-nuclear profile of molecules,cellular compartments, or organelles are homogenized in standard waysknown for those skilled in the art. In some embodiments, differentfractionation procedures are used to enrich the fractions of molecules.In one embodiment, the molecules obtained are passed over severalfractionation columns. In one embodiment, the fractionation columnsemploy a variety of detectors used in tandem or parallel to generate themolecule profile for the organ, cell, cellular compartment, ororganelle.

As used herein the term “disease” refers to any condition which wouldbenefit from treatment with the antibody.

In one embodiment, the present invention concerns a method for treating,diagnosing, prognosticating or determining the suitability for treatmentof a subject suffering from cancer, specifically AML.

As used herein, “cancer” or “pre-malignancy” are diseases associatedwith cell proliferation. Non-limiting types of cancer include carcinoma,sarcoma, lymphoma, leukemia, blastoma and germ cells tumors. In oneembodiment, carcinoma refers to tumors derived from epithelial cellsincluding but not limited to breast cancer, prostate cancer, lungcancer, pancreas cancer, and colon cancer. In one embodiment, sarcomarefers of tumors derived from mesenchymal cells including but notlimited to sarcoma botryoides, chondrosarcoma, Ewing's sarcoma,malignant hemangioendothelioma, malignant schwannoma, osteosarcoma andsoft tissue sarcomas. In one embodiment, lymphoma refers to tumorsderived from hematopoietic cells that leave the bone marrow and tend tomature in the lymph nodes including but not limited to Hodgkin lymphoma,non-Hodgkin lymphoma, multiple myeloma and immunoproliferative diseases.In one embodiment, leukemia refers to tumors derived from hematopoieticcells that leave the bone marrow and tend to mature in the bloodincluding but not limited to acute lymphoblastic leukemia, chroniclymphocytic leukemia, acute myelogenous leukemia, chronic myelogenousleukemia, hairy cell leukemia, T-cell prolymphocytic leukemia, largegranular lymphocytic leukemia and adult T-cell leukemia. In oneembodiment, blastoma refers to tumors derived from immature precursorcells or embryonic tissue including but not limited to hepatoblastoma,medulloblastoma, nephroblastoma, neuroblastoma, pancreatoblastoma,pleuropulmonary blastoma, retinoblastoma and glioblastoma-multiforme. Inone embodiment, germ cell tumors refer to tumors derived from germ cellsincluding but not limited to germinomatous or seminomatous germ celltumors (GGCT, SGCT) and nongerminomatous or nonseminomatous germ celltumors (NGGCT, NSGCT). In one embodiment, germinomatous or seminomatoustumors include but not limited to germinoma, dysgerminoma and seminoma.In one embodiment, non-germinomatous or nonseminomatous tumors refers topure and mixed germ cells tumors including but not limited to embryonalcarcinoma, endodermal sinus tumor, choriocarcinoma, tearoom,polyembryoma, gonadoblastoma and teratocarcinoma.

In some embodiments, monoclonal antibodies of the present invention areuseful for the diagnosis, detection, staging, and therapy of a disease.In some embodiments, monoclonal antibodies of the present invention areuseful for the diagnosis, detection, staging, and therapy of a humandisease. In some embodiments, monoclonal antibodies of the presentinvention are useful for the diagnosis, detection, staging, and therapyof cancer.

In one embodiment, the monoclonal antibodies and fragments thereof ofthe present invention are humanized or fully human.

In some embodiment, the present invention provides a method ofdiagnosing or treating a malignancy in a subject comprisingadministering to the subject a therapeutically effective amount of atherapeutic conjugate comprising the monoclonal antibodies of thepresent invention or fragment thereof or an antibody fusion protein orfragment thereof, wherein the monoclonal antibodies of the presentinvention or fragment thereof or antibody fusion protein or fragmentthereof is bound to at least one diagnostic and/or therapeutic agent andthen formulated in a pharmaceutically suitable excipient.

The use of monoclonal antibodies for in-vitro diagnosis is well-known toone skilled in the art. For example, see Carlsson et al., Bio/Technology7 (6): 567 (1989). For example, monoclonal antibodies can be used todetect the presence of a tumor-associated antigen in tissue from biopsysamples. Monoclonal antibodies also can be used to measure the amount oftumor-associated antigen in clinical fluid samples using techniques suchas radioimmunoassay, enzyme-linked immunosorbent assay, and fluorescenceimmunoassay. Conjugates of tumor-targeted monoclonal antibodies andtoxins can be used to selectively kill cancer cells in vivo (Spalding,Bio/Technology 9(8): 701 (1991); Goldenberg, Scientific American Science& Medicine 1(1): 64 (1994)). For example, therapeutic studies inexperimental animal models have demonstrated the anti-tumor activity ofantibodies carrying cytotoxic radionuclides.

Also described herein is a cancer cell targeting diagnostic ortherapeutic conjugate comprising an antibody component that comprises amonoclonal antibody or fragment thereof of any of the antibodies of thepresent invention, or an antibody fusion protein or fragment thereof,wherein the antibody component is bound to at least one diagnostic or atleast one therapeutic agent. In one embodiment, the diagnostic conjugateis a photoactive diagnostic/detection agent. In one embodiment, thediagnostic conjugate is an ultrasound detectable agent. In oneembodiment, the diagnostic conjugate is an MRI contrast agent. Inanother embodiment, the diagnostic/detection agent is a radionuclidewith an energy between 20 and 4,000 keV.

Furthermore, the present invention includes methods of diagnosing cancerin a subject. In some embodiments, diagnosis is accomplished byadministering a diagnostically effective amount of a diagnosticconjugate, formulated in a pharmaceutically suitable excipient, anddetecting said label. The monoclonal antibodies of the present inventionor derived fusion proteins or fragments thereof may be conjugated to thediagnostic/detection agent or be administered unconjugated to thediagnostic/detection agent, but before, concurrently, or afteradministration of the diagnostic/detection agent. In one embodiment, asuitable non-radioactive diagnostic/detection agent is a contrast agentsuitable for magnetic resonance imaging (MRI), X-rays, computedtomography (CT) or ultrasound. In another embodiment, magnetic imagingagents include, for example, non-radioactive metals, such as manganese,iron and gadolinium, complexed with metal-chelate combinations thatinclude 2-benzyl-DTPA and its monomethyl and cyclohexyl analogs, whenused along with the antibodies of the invention. See U.S. Ser. No.09/921,290 filed on Oct. 10, 2001, which is incorporated in its entiretyby reference.

In some embodiments, contrast agents, such as MRI contrast agents,contemplated in the present invention include, but not limited to,gadolinium ions, lanthanum ions, dysprosium ions, iron ions, manganeseions or other comparable label, CT contrast agents, and ultrasoundcontrast agents. In another embodiment, paramagnetic ions are suitablefor the present invention. In one embodiment, paramagnetic ions includechromium³⁺, manganese²⁺, iron³⁺, iron²⁺, cobalt²⁺, nickel²⁺, copper²⁺,neodymium³⁺, samarium³⁺, ytterbium³⁺, gadolinium³⁺, vanadium²⁺,terbium³⁺, dysprosium³⁺, holmium³⁺ and erbium³⁺, with gadolinium beingparticularly preferred. In another embodiment, ions useful in othercontexts, such as X-ray imaging, include but are not limited tolanthanum³⁺, gold³⁺, lead²⁺, and especially bismuth³⁺. In anotherembodiment, metals are also useful in diagnostic/detection agents,including those for magnetic resonance imaging techniques. In oneembodiment, these metals include, but are not limited to: Gadolinium,manganese, iron, chromium, copper, cobalt, nickel, dysprosium, rhenium,europium, terbium, holmium and neodymium. In another embodiment, loadingan antibody component with radioactive metals or paramagnetic ions mayrequire reacting the antibody with a reagent having a long tail to whichare attached a multiplicity of chelating groups for binding the ions. Inone embodiment, such a tail can be a polymer such as a polylysine,polysaccharide, or other derivatized or derivatizable chain havingpendant groups to which can be bound chelating groups such as, e.g.,ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaaceticacid (DTPA), porphyrins, polyamines, crown ethers,bis-thiosemicarbazones, polyoximes, and like groups known to be usefulfor this purpose.

In some embodiments, conjugated diagnostic agents are radiopaque andcontrast materials. In one embodiment these radiopaque diagnostic agentsare used for enhancing X-rays and computed tomography, and includeiodine compounds, barium compounds, gallium compounds, thalliumcompounds, etc. In another embodiment, specific compounds includebarium, diatrizoate, ethiodized oil, gallium citrate, iocarmic acid,iocetamic acid, iodamide, iodipamide, iodoxamic acid, iogulamide,iohexol, iopamidol, iopanoic acid, ioprocemic acid, iosefamic acid,ioseric acid, iosulamide meglumine, iosemetic acid, iotasul, iotetricacid, iothalamic acid, iotroxic acid, ioxaglic acid, ioxotrizoic acid,ipodate, meglumine, metrizamide, metrizoate, propyliodone, and thallouschloride.

In some embodiments, the conjugated diagnostic agent is a fluorescentagent. In another embodiment, fluorescent labeling compounds includefluorescein isothiocyanate, rhodamine, phycoerytherin, renographin,phycocyanin, allophycocyanin, o-phthaldehyde and fluorescamine. In oneembodiment, rhodamine and fluorescein are often linked via anisothiocyanate intermediate. In one embodiment, fluorescently-labeledantibodies are particularly used for flow cytometry analysis.

In some embodiments, the antibodies, fusion proteins, and fragmentsthereof of this invention can be detectably labeled by coupling theantibody to a chemiluminescent compound. In one embodiment,chemiluminescent labeling compounds include, but are not limited to,luminol, isoluminol, an aromatic acridinium ester, an imidazole, anacridinium salt and an oxalate ester, and others.

In some embodiments, a bioluminescent compound can be used to label theantibodies and fragments thereof the present invention. In oneembodiment, bioluminescent labeling compounds include, but are notlimited to luciferin, luciferase and aequorin.

According to another aspect, the present invention provides a method oftreatment of a subject suffering from a disease, the method comprisesadministering to said subject a therapeutically effective amount of atleast one antibody, fusion protein and fragments thereof of theinvention directed against NKp44 isoform 1, or any fragment thereof.

The term “a therapeutically effective amount” refers to an amounteffective, at dosages and for periods of time necessary, to achieve thedesired therapeutic or prophylactic result. The exact dosage form andregimen would be determined by the physician according to the patient'scondition.

Pharmaceutical Compositions

The present invention also contemplates pharmaceutical formulations forhuman medical use, which comprise as the active agent at least oneantibody which recognizes PCNA, for the manufacture of a therapeuticcomposition for the treatment, diagnosis or prophylaxis of theconditions variously described herein.

In such pharmaceutical and medicament formulations, the active agent ispreferably utilized together with one or more pharmaceuticallyacceptable carrier(s) and optionally any other therapeutic ingredients.The carrier(s) must be pharmaceutically acceptable in the sense of beingcompatible with the other ingredients of the formulation and not undulydeleterious to the recipient thereof. The active agent is provided in anamount effective to achieve the desired pharmacological effect, asdescribed above, and in a quantity appropriate to achieve the desireddaily dose.

Typically, the molecules of the present invention comprising the antigenbinding portion of an antibody will be suspended in a sterile salinesolution for therapeutic uses. The pharmaceutical compositions mayalternatively be formulated to control release of active ingredient(molecule comprising the antigen binding portion of an antibody) or toprolong its presence in a patient's system. Numerous suitable drugdelivery systems are known and include, e.g., implantable drug releasesystems, hydrogels, hydroxymethylcellulose, microcapsules, liposomes,microemulsions, microspheres, and the like. Controlled releasepreparations can be prepared through the use of polymers to complex oradsorb the molecule according to the present invention. For example,biocompatible polymers include matrices of poly(ethylene-co-vinylacetate) and matrices of a polyanhydride copolymer of a stearic aciddimer and sebaric acid. The rate of release of the molecule according tothe present invention, i.e., of an antibody or antibody fragment, fromsuch a matrix depends upon the molecular weight of the molecule, theamount of the molecule within the matrix, and the size of dispersedparticles.

The pharmaceutical composition of this invention may be administered byany suitable means, such as orally, topically, intranasally,subcutaneously, intramuscularly, intravenously, intra-arterially,intraarticulary, intralesionally or parenterally. Ordinarily,intravenous (i.v.), intraarticular, topical or parenteral administrationwill be preferred.

It will be apparent to those of ordinary skill in the art that thetherapeutically effective amount of the molecule according to thepresent invention will depend, inter alia upon the administrationschedule, the unit dose of molecule administered, whether the moleculeis administered in combination with other therapeutic agents, the immunestatus and health of the patient, the therapeutic activity of themolecule administered and the judgment of the treating physician.

Although an appropriate dosage of a molecule (an antibody or a fragmentthereof) of the invention varies depending on the administration route,type of molecule (polypeptide, polynucleotide, organic molecule etc.)age, body weight, sex, or conditions of the patient, and should bedetermined by the physician in the end, in the case of oraladministration, the daily dosage can generally be between about 0.01 mgto about 500 mg, preferably about 0.01 mg to about 50 mg, morepreferably about 0.1 mg to about 10 mg, per kg body weight. In the caseof parenteral administration, the daily dosage can generally be betweenabout 0.001 mg to about 100 mg, preferably about 0.001 mg to about 10mg, more preferably about 0.01 mg to about 1 mg, per kg body weight. Thedaily dosage can be administered, for example in regimens typical of 1-4individual administration daily. Other preferred methods ofadministration include intraarticular administration of about 0.01 mg toabout 100 mg per kg body weight. Various considerations in arriving atan effective amount are described, e.g., in Goodman and Gilman's: ThePharmacological Bases of Therapeutics, 8th ed., Pergamon Press, 1990;and Remington's Pharmaceutical Sciences, 17th ed., Mack Publishing Co.,Easton, Pa., 1990.

Suitable dosing regimens of combination chemotherapies are known in theart and described in, for example, Saltz et al. Proc ASCO 1999, 18, 233aand Douillard et al., Lancet 2000, 355, 1041-7.

The molecules of the present invention as active ingredients aredissolved, dispersed or admixed in an excipient that is pharmaceuticallyacceptable and compatible with the active ingredient as is well known.Suitable excipients are, for example, water, saline, phosphate bufferedsaline (PBS), dextrose, glycerol, ethanol, or the like and combinationsthereof. Other suitable carriers are well known to those skilled in theart. In addition, if desired, the composition can contain minor amountsof auxiliary substances such as wetting or emulsifying agents, pHbuffering agents.

According to another aspect, the invention provides a pharmaceuticalcomposition comprising as an active ingredient a therapeuticallyeffective amount of the polypeptide of the present invention, andpharmaceutically acceptable carrier and/or diluents. In someembodiments, the pharmaceutical composition facilitates administrationof a compound to an organism.

In another embodiment, the pharmaceutical compositions of the inventionmay be formulated in the form of a pharmaceutically acceptable salt ofthe polypeptides of the present invention or their analogs, orderivatives thereof. In another embodiment, pharmaceutically acceptablesalts include those salts formed with free amino groups such as saltsderived from non-toxic inorganic or organic acids such as hydrochloric,phosphoric, acetic, oxalic, tartaric acids, and the like, and thosesalts formed with free carboxyl groups such as salts derived fromnon-toxic inorganic or organic bases such as sodium, potassium,ammonium, calcium, ferric hydroxides, isopropylamine, triethylamine,2-ethylamino ethanol, histidine, procaine, and the like.

As used herein, the term “carrier” refers to a diluent, adjuvant,excipient, or vehicle with which the therapeutic compound isadministered. Such pharmaceutical carriers can be sterile liquids, suchas water and oils, including those of petroleum, animal, vegetable orsynthetic origin, such as peanut oil, soybean oil, mineral oil, sesameoil and the like, polyethylene glycols, glycerin, propylene glycol orother synthetic solvents. Water is a preferred carrier when thepharmaceutical composition is administered intravenously. Salinesolutions and aqueous dextrose and glycerol solutions can also beemployed as liquid carriers, particularly for injectable solutions.Suitable pharmaceutical excipients include starch, glucose, lactose,sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate,glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol,propylene glycol, water, ethanol and the like. The composition, ifdesired, can also contain minor amounts of wetting or emulsifyingagents, or pH buffering agents such as acetates, citrates or phosphates.Antibacterial agents such as benzyl alcohol or methyl parabens;antioxidants such as ascorbic acid or sodium bisulfite; and agents forthe adjustment of tonicity such as sodium chloride or dextrose are alsoenvisioned. The carrier may comprise, in total, from about 0.1% to about99.99999% by weight of the pharmaceutical compositions presented herein.

As used herein, the term “pharmaceutically acceptable” means suitablefor administration to a subject, e.g., a human. For example, the term“pharmaceutically acceptable” can mean approved by a regulatory agencyof the Federal or a state government or listed in the U. S. Pharmacopeiaor other generally recognized pharmacopeia for use in animals, and moreparticularly in humans.

In another embodiment, the compositions of the invention take the formof solutions, suspensions, emulsions, tablets, pills, capsules, powders,gels, creams, ointments, foams, pastes, sustained-release formulationsand the like. In another embodiment, the compositions of the inventioncan be formulated as a suppository, with traditional binders andcarriers such as triglycerides, microcrystalline cellulose, gumtragacanth or gelatin. Oral formulation can include standard carrierssuch as pharmaceutical grades of mannitol, lactose, starch, magnesiumstearate, sodium saccharine, cellulose, magnesium carbonate, etc.Examples of suitable pharmaceutical carriers are described in:Remington's Pharmaceutical Sciences” by E. W. Martin, the contents ofwhich are hereby incorporated by reference herein. Such compositionswill contain a therapeutically effective amount of the polypeptide ofthe invention, preferably in a substantially purified form, togetherwith a suitable amount of carrier so as to provide the form for properadministration to the subject.

According to an embodiment of the invention, pharmaceutical compositionscontain 0.1%-95% of the polypeptide(s) of the present invention,derivatives, or analogs thereof. According to another embodiment of theinvention, pharmaceutical compositions contain 1%-70% of thepolypeptide(s) derivatives, or analogs thereof. According to anotherembodiment of the invention, the composition or formulation to beadministered may contain a quantity of polypeptide(s), derivatives, oranalogs thereof, according to embodiments of the invention in an amounteffective to treat the condition or disease of the subject beingtreated.

An embodiment of the invention relates to polypeptides of the presentinvention, derivatives, or analogs thereof, presented in unit dosageform and prepared by any of the methods well known in the art ofpharmacy. In an embodiment of the invention, the unit dosage form is inthe form of a tablet, capsule, lozenge, wafer, patch, ampoule, vial orpre-filled syringe. In addition, in vitro assays may optionally beemployed to help identify optimal dosage ranges. The precise dose to beemployed in the formulation will also depend on the route ofadministration, and the nature of the disease or disorder, and should bedecided according to the judgment of the practitioner and each patient'scircumstances. Effective doses can be extrapolated from dose-responsecurves derived from in-vitro or in-vivo animal model test bioassays orsystems.

According to one embodiment, the compositions of the present inventionare administered in the form of a pharmaceutical composition comprisingat least one of the active components of this invention (the chimericpolypeptides) together with a pharmaceutically acceptable carrier ordiluent. In another embodiment, the compositions of this invention canbe administered either individually or together in any conventionaloral, parenteral or transdermal dosage form. In some embodiments, thepharmaceutical composition further comprises at least one anticanceragent such as a chemotherapeutic agent. In some embodiments, thepharmaceutical composition is adopted for combined administration withan anticancer therapy such as chemotherapy, radiotherapy, immunotherapy,hormonal therapy, toxin therapy or surgery.

As used herein, the terms “administering,” “administration,” and liketerms refer to any method which, in sound medical practice, delivers acomposition containing an active agent to a subject in such a manner asto provide a therapeutic effect.

Depending on the location of the tissue of interest, the polypeptide ofthe present invention can be administered in any manner suitable for theprovision of the polypeptides to cells within the tissue of interest.Thus, for example, a composition containing the polypeptides of thepresent invention can be introduced, for example, into the systemiccirculation, which will distribute the peptide to the tissue ofinterest. Alternatively, a composition can be applied topically to thetissue of interest (e.g., injected, or pumped as a continuous infusion,or as a bolus within a tissue, applied to all or a portion of thesurface of the skin, etc.).

In some embodiments, the pharmaceutical compositions comprising thechimeric polypeptides are administered via oral, rectal, vaginal,topical, nasal, ophthalmic, transdermal, subcutaneous, intramuscular,intraperitoneal or intravenous routes of administration. The route ofadministration of the pharmaceutical composition will depend on thedisease or condition to be treated. Suitable routes of administrationinclude, but are not limited to, parenteral injections, e.g.,intradermal, intravenous, intramuscular, intralesional, subcutaneous,intrathecal, and any other mode of injection as known in the art.Although the bioavailability of peptides administered by other routescan be lower than when administered via parenteral injection, by usingappropriate formulations it is envisaged that it will be possible toadminister the compositions of the invention via transdermal, oral,rectal, vaginal, topical, nasal, inhalation and ocular modes oftreatment. In addition, it may be desirable to introduce thepharmaceutical compositions of the invention by any suitable route,including intraventricular and intrathecal injection; intraventricularinjection may be facilitated by an intraventricular catheter, forexample, attached to a reservoir. Pulmonary administration can also beemployed, e.g., by use of an inhaler or nebulizer.

For topical application, a peptide of the present invention, derivative,analog or a fragment thereof can be combined with a pharmaceuticallyacceptable carrier so that an effective dosage is delivered, based onthe desired activity. The carrier can be in the form of, for example,and not by way of limitation, an ointment, cream, gel, paste, foam,aerosol, suppository, pad or gelled stick.

For oral applications, the pharmaceutical composition may be in the formof tablets or capsules, which can contain any of the followingingredients, or compounds of a similar nature: a binder such asmicrocrystalline cellulose, gum tragacanth or gelatin; an excipient suchas starch or lactose; a disintegrating agent such as alginic acid,Primogel, or corn starch; a lubricant such as magnesium stearate; or aglidant such as colloidal silicon dioxide. When the dosage unit form isa capsule, it can contain, in addition to materials of the above type, aliquid carrier such as fatty oil. In addition, dosage unit forms cancontain various other materials which modify the physical form of thedosage unit, for example, coatings of sugar, shellac, or other entericagents. The tablets of the invention can further be film coated.

For purposes of parenteral administration, solutions in sesame or peanutoil or in aqueous propylene glycol can be employed, as well as sterileaqueous solutions of the corresponding water-soluble salts. Such aqueoussolutions may be suitably buffered, if necessary, and the liquid diluentfirst rendered isotonic with sufficient saline or glucose. These aqueoussolutions are especially suitable for intravenous, intramuscular,subcutaneous and intraperitoneal injection purposes.

According to some embodiments, the chimeric polypeptides of the presentinvention, derivatives, or analogs thereof can be delivered in acontrolled release system. In another embodiment, an infusion pump canbe used to administer the peptide such as the one that is used, forexample, for delivering insulin or chemotherapy to specific organs ortumors. In another embodiment, the peptides of the invention areadministered in combination with a biodegradable, biocompatiblepolymeric implant, which releases the peptide over a controlled periodof time at a selected site. Examples of preferred polymeric materialsinclude, but are not limited to, polyanhydrides, polyorthoesters,polyglycolic acid, polylactic acid, polyethylene vinyl acetate,copolymers and blends thereof (See, Medical applications of controlledrelease, Langer and Wise (eds.), 1974, CRC Pres., Boca Raton, Fla., thecontents of which are hereby incorporated by reference in theirentirety). In yet another embodiment, a controlled release system can beplaced in proximity to a therapeutic target, thus requiring only afraction of the systemic dose.

The presently described peptides, derivatives, or analogs thereof mayalso be contained in artificially created structures such as liposomes,ISCOMS, slow-releasing particles, and other vehicles which increase thehalf-life of the peptides or polypeptides in serum. Liposomes includeemulsions, foams, micelles, insoluble monolayers, liquid crystals,phospholipid dispersions, lamellar layers and the like. Liposomes foruse with the presently described peptides are formed from standardvesicle-forming lipids which generally include neutral and negativelycharged phospholipids and a sterol, such as cholesterol. The selectionof lipids is generally determined by considerations such as liposomesize and stability in the blood. A variety of methods are available forpreparing liposomes as reviewed, for example, by Coligan, J. E. et al,Current Protocols in Protein Science, 1999, John Wiley & Sons, Inc., NewYork, and see also U.S. Pat. Nos. 4,235,871, 4,501,728, 4,837,028, and5,019,369.

The compositions also include incorporation of the active material intoor onto particulate preparations of polymeric compounds such aspolylactic acid, polglycolic acid, hydrogels, etc, or onto liposomes,microemulsions, micelles, unilamellar or multilamellar vesicles,erythrocyte ghosts, or spheroplasts. Such compositions will influencethe physical state, solubility, stability, rate of in vivo release, andrate of in vivo clearance.

In one embodiment, the present invention provides combined preparations.In one embodiment, “a combined preparation” defines especially a “kit ofparts” in the sense that the combination partners as defined above canbe dosed independently or by use of different fixed combinations withdistinguished amounts of the combination partners i.e., simultaneously,concurrently, separately or sequentially. In some embodiments, the partsof the kit of parts can then, e.g., be administered simultaneously orchronologically staggered, that is at different time points and withequal or different time intervals for any part of the kit of parts. Theratio of the total amounts of the combination partners, in someembodiments, can be administered in the combined preparation. In oneembodiment, the combined preparation can be varied, e.g., in order tocope with the needs of a patient subpopulation to be treated or theneeds of the single patient which different needs can be due to aparticular disease, severity of a disease, age, sex, or body weight ascan be readily made by a person skilled in the art.

In one embodiment, it will be appreciated that the peptides of thepresent invention can be provided to the individual with additionalactive agents to achieve an improved therapeutic effect as compared totreatment with each agent by itself. In another embodiment, measures(e.g., dosing and selection of the complementary agent) are taken toadverse side effects which are associated with combination therapies.

In one embodiment, depending on the severity and responsiveness of thecondition to be treated, dosing can be of a single or a plurality ofadministrations, with course of treatment lasting from several days toseveral weeks or until cure is affected or diminution of the diseasestate is achieved.

In some embodiments, the peptides are administered in a therapeuticallysafe and effective amount. As used herein, the term “safe and effectiveamount” refers to the quantity of a component which is sufficient toyield a desired therapeutic response without undue adverse side effects(such as toxicity, irritation, or allergic response) commensurate with areasonable benefit/risk ratio when used in the presently describedmanner. In another embodiment, a therapeutically effective amount of thepolypeptide is the amount of the polypeptide necessary for the in vivomeasurable expected biological effect. The actual amount administered,and the rate and time-course of administration, will depend on thenature and severity of the condition being treated. Prescription oftreatment, e.g. decisions on dosage, timing, etc., is within theresponsibility of general practitioners or specialists, and typicallytakes account of the disorder to be treated, the condition of theindividual patient, the site of delivery, the method of administrationand other factors known to practitioners. Examples of techniques andprotocols can be found in Remington: The Science and Practice ofPharmacy, 21st Ed., Lippincott Williams & Wilkins, Philadelphia, Pa.,(2005). In some embodiments, preparation of effective amount or dose canbe estimated initially from in vitro assays. In one embodiment, a dosecan be formulated in animal models and such information can be used tomore accurately determine useful doses in humans.

In one embodiment, toxicity and therapeutic efficacy of the activeingredients described herein can be determined by standardpharmaceutical procedures in vitro, in cell cultures or experimentalanimals. In one embodiment, the data obtained from these in vitro andcell culture assays and animal studies can be used in formulating arange of dosage for use in human. In one embodiment, the dosages varydepending upon the dosage form employed and the route of administrationutilized. In one embodiment, the exact formulation, route ofadministration and dosage can be chosen by the individual physician inview of the patient's condition. [See e.g., Fingl, et al., (1975) “ThePharmacological Basis of Therapeutics”, Ch. 1 p. 1].

Pharmaceutical compositions containing the presently describedpolypeptide as the active ingredient can be prepared according toconventional pharmaceutical compounding techniques. See, for example,Remington's Pharmaceutical Sciences, 18th Ed., Mack Publishing Co.,Easton, Pa. (1990). See also, Remington: The Science and Practice ofPharmacy, 21st Ed., Lippincott Williams & Wilkins, Philadelphia, Pa.(2005).

In one embodiment, compositions including the preparation of the presentinvention formulated in a compatible pharmaceutical carrier areprepared, placed in an appropriate container, and labeled for treatmentof an indicated condition.

In one embodiment, compositions of the present invention are presentedin a pack or dispenser device, such as an FDA approved kit, whichcontains, one or more unit dosages forms containing the activeingredient. In one embodiment, the pack, for example, comprises metal orplastic foil, such as a blister pack. In one embodiment, the pack ordispenser device is accompanied by instructions for administration. Inone embodiment, the pack or dispenser is accommodated by a noticeassociated with the container in a form prescribed by a governmentalagency regulating the manufacture, use or sale of pharmaceuticals, whichnotice is reflective of approval by the agency of the form of thecompositions or human or veterinary administration. Such notice, in oneembodiment, is labeling approved by the U.S. Food and DrugAdministration for prescription drugs or of an approved product insert.

The following examples are intended to illustrate how to make and usethe compounds and methods of this invention and are in no way to beconstrued as a limitation. Although the invention will now be describedin conjunction with specific embodiments thereof, it is evident thatmany modifications and variations will be apparent to those skilled inthe art. Accordingly, it is intended to embrace all such modificationsand variations that fall within the spirit and broad scope of theappended claims.

EXAMPLES

Generally, the nomenclature used herein, and the laboratory proceduresutilized in the present invention include molecular, biochemical,microbiological and recombinant DNA techniques. Such techniques arethoroughly explained in the literature. See, for example, “MolecularCloning: A laboratory Manual” Sambrook et al., (1989); “CurrentProtocols in Molecular Biology” Volumes I-III Ausubel, R. M., ed.(1994); Ausubel et al., “Current Protocols in Molecular Biology”, JohnWiley and Sons, Baltimore, Md. (1989); Perbal, “A Practical Guide toMolecular Cloning”, John Wiley & Sons, New York (1988); Watson et al.,“Recombinant DNA”, Scientific American Books, New York; Birren et al.(eds) “Genome Analysis: A Laboratory Manual Series”, Vols. 1-4, ColdSpring Harbor Laboratory Press, New York (1998); methodologies as setforth in U.S. Pat. Nos. 4,666,828; 4,683,202; 4,801,531; 5,192,659 and5,272,057; “Cell Biology: A Laboratory Handbook”, Volumes I-III Cellis,J. E., ed. (1994); “Culture of Animal Cells—A Manual of Basic Technique”by Freshney, Wiley-Liss, N. Y. (1994), Third Edition; “Current Protocolsin Immunology” Volumes I-III Coligan J. E., ed. (1994); Stites et al.(eds), “Basic and Clinical Immunology” (8th Edition), Appleton & Lange,Norwalk, Conn. (1994); Mishell and Shiigi (eds), “Strategies for ProteinPurification and Characterization—A Laboratory Course Manual” CSHL Press(1996); “Monoclonal Antibodies: Methods and Protocols”. Vincent Ossipow,Nicolas Fischer. Humana Press (2014); “Monoclonal Antibodies: Methodsand Protocols”. Maher Albitar. Springer Science & Business Media (2007),all of which are incorporated by reference. Other general references areprovided throughout this document.

Materials and Methods

Recombinant Human PCNA Production

The pET-28 or pMAL-c2x vectors were used to produce recombinant humanPCNA (hPCNA) in Rosetta™ 2 (DE3) cells. Plasmids containing the mRNAsequence of PCNA were transformed into Rosetta™ 2 cells via heat shockand grown on LB+Kan+CP agar plates. A fresh colony of transformedbacteria was grown overnight in a 5 ml of LB+Kan+CP in an incubatorshaker set to 37° C. and at 250 rpm. The next day, bacteria calls werediluted 1:100 into a 500 ml of LB+Kan+CP (to discard dead cells) andgrown to an O.D. of 0.6-0.8 (λ=650 nm). Isopropylβ-D-1-thiogalactopyranoside (IPTG) was added for the induction of thePCNA (0.5 mM) and cells were further incubated for 4 h at 26° C.(hPCNA). Cells were then centrifuged, and the pellet was resuspendedwith solution A (20 mM Tris-HCl pH 8.0, 0.5 M NaCl, 20 mM Imidazole),sonicated six times (20 seconds with 40 seconds intervals) and sievedthrough 0.45 μm (Sartorius Stedimbiotech) filter before loaded on aHis-tag or Amyloseresin beads. Purification of His-tagged proteins wasdone using a Gravity-flow Column with “HisPur™ Ni-NTA Resin” Bead kit(Thermo-Scientific; Binding Capacity ≤60 mg of a 28 kDa 6×His-taggedprotein from a bacterial source per milliliter of settled resin)according to kit's protocol. Purification of MBP-tagged proteins wasdone using the Amylose resin beads (Catalog # E8035S).

Kinetic Analysis of the Antibody by Surface Plasmon Resonance

A ProteOn™ XPR36 Protein Interaction Array System (Bio-Rad) was used tomeasure the affinity of the monoclonal antibody 14-25-9 to his-taggedrecombinant PCNA. For the assay, a HTG chip and ProteOn Manager Version3.1.0.6 (Bio-Rad Laboratories) was employed. After activation of thechip using EDC/S-NHS amine coupling procedure the ligand immobilizationprocess was performed with his-tagged recombinant PCNA and His-taggedIL-2 as a control at a flow rate of 30 μl/min in different flow cells.Different analyte (14-25-9) concentrations (100-0 nM) were injected at aflow rate of 40 μl/min, each followed by regeneration of the surfaceusing 50 mM NaOH. Data were analyzed using the Bivalent binding model.

Cell Lines and Cell Culture

The following cell lines were used: A549, human lung adenocarcinoma(American Type Culture Collection CCL-185); HeLa, human cervicaladenocarcinoma (ATCC CCL-2); MDA-MB-435, human melanoma(https://www.atcc.org/Products/All/HTB-129.aspx) (ATCC HTB-129); K562,human chronic myelogenous leukemia (ATCC CCL-243) and 721.221cw6, stable721.221 (MEW class I-negative human B cell line) transfectantsexpressing HLA-C molecules as generated previously (J Exp Med. 1996 Sep.1; 184(3):913-22). Cells were cultured in either DMEM or RPMI-1640(Gibco, Life Technologies) medium supplemented with 10% FBS and 1%penicillin/streptomycin. Human NK cell leukemia derived NK-92 cell line(ATCC CRL-2407) was retrovirally transduced with the FLAG-tagged NKp44constructs to produce NK-92-NKp44 cell line. Retroviral transduction wasperformed as previously described. Stable NK-92-NKp44 cell line was thencultured in alpha-MEM medium (Gibco, Life Technologies) supplementedwith 10% horse serum, 10% FBS, 0.2 mM myo-inositol (Sigma), 0.1 mMβ-mercaptoethanol (Sigma), 20 μM folic acid (Fisher Scientific), 100IU/ml of recombinant human IL-2 (PeproTech), and 1%penicillin/streptomycin (Life Technologies).

Isolation and Culture of Primary Human NK Cells

With prior approval from the Ben-Gurion University of the NegevInstitutional Review Board, human primary natural killer cell isolationwas done from peripheral blood of healthy volunteer donors with theirinformed consent, using the RosetteSep Human NK cell Enrichment Cocktailkit (Stem Cell Technologies). After purification, cells were cultured inCellGro stem cell serum-free growth medium (CellGenix) supplemented with10% heat-inactivated human plasma from healthy donors, 1 mM sodiumpyruvate, 2 mM L-glutamine, 1×MEM non-essential amino acids, 1%penicillin/streptomycin, 10 mM HEPES (Life Technologies), and 300 IU/mlhuman IL-2 (PeproTech).

ELISA for IFN-γ Secretion Assay

A paired set of purified and biotinylated anti-human IFN-γ antibody(BioLegend) was used for the sandwich ELISA of IFN-γ secretion assay.96-well U-bottom plates (NUNC) were pre-coated with either 0.5 μg/mlAnti-human NKp30 mAb (R&D Systems) diluted in Na₂HPO₄ buffer (0.1 M, pH9) or only buffer for 18 h at 4° C. Tumor cells were incubated eitherwith 1×PBS, anti-mouse IgG1 or different conc. of 14-25-9 mAb (2, 5 and10 μg/ml in studies using primary NK cells and 10, 20 and 30 μg/ml whileNK-92-NKp44 cell line). Then they were co-cultured (Effector:Targetratio 1:3) with either primary human NK cells or NK-92-NKp44 in thepreviously coated 96-well U-bottom plates for 18 h in a 37° C., 5% CO₂incubator. Post incubation, the supernatant from each well wastransferred to corresponding wells in 96-well flat-bottom ELISA platescoated previously with 0.25 μg/ml purified anti-human IFN-γ, incubatedand recaptured using 0.25 μg/ml biotinylated anti-human IFN-γ. CapturedIFN-γ was quantitated using HRP-tagged streptavidin (JacksonImmunoResearch) and TMB substrate (Dako) in a multiplate ELISA reader.

Flow Cytometry Based NK Cell-Mediated Lysis Assay

As in the IFN-γ secretion assay, carboxyfluorescein diacetatesuccinimidyl ester-stained (CellTrace™ CFSE Cell Proliferation Kit,Thermo) tumor cells were incubated initially either with 1×PBS,anti-mouse IgG1 or different conc. of 14-25-9 mAb and then co-culturedwith primed primary human NK cells or NK-92-NKp44 cells in 96-wellU-bottom plates pre-coated with either 0.5μg/ml anti-human NKp30 mAb orbuffer for 4 h (37° C., 5% CO₂). Assay analysis was based on followinggating strategy: CFSE-positive tumor cells were subjected to Live/Deaddiscrimination (PI negative or positive staining in accordance). Thepercentage of specific cytotoxicity was calculated as follows (Journalof Immunological Methods 2001 253:177-187):

${\%\mspace{14mu}{Specific}\mspace{14mu}{Lysis}} = \frac{100 \times \left( {{\%\mspace{14mu}{Sample}\mspace{14mu}{Lysis}} - {\%\mspace{14mu}{Basal}\mspace{14mu}{Lysis}}} \right)}{100 - {\%\mspace{14mu}{Basal}\mspace{14mu}{Lysis}}}$

Example 1 NKp44-1 has a Unique Role as an Immune Checkpoint

Previous reports have shown that tumor-expressed PCNA can be utilized bycancer cells to suppress NK activity, through interaction with the NKreceptor NCR2/NKp44. To assess the role of each NKp44 splice variant,NK92 cells were transfected with cDNA encoding for each of the threeNKp44 splice variants. qPCR analysis of the splice variants profile ofthe three NK92 transfectants, (i.e., NK92-44-1, NK92-44-2 and NK92-44-3)showed dominant expression of the transfected splice variant in allthree.

Over-expression of PCNA by co-cultured (target) cells inhibited IFNγsecretion by NK92-44-1 cells, but not by NK92-44-2 and NK92-44-3 cells(FIG. 1A). The inventors next explored whether PCNA-impaired andPCNA-responsive NK functional phenotypes can influence the cytoskeletonrearrangement that is necessary for the formation of stable lytic immunesynapses. Stable lytic immune synapse formation was examined in eachNKp44 splice variant-transfected NK92 cell lines. NK92 wt (parental),NK92-44-1, NK92-44-2 and NK92-44-3 (effector) cells were co-incubatedwith HeLa cells expressing CFP alone or CFP-PCNA fusion protein and therelative accumulation of F-actin at the immune synapse was assessed(FIG. 1B, C). It was surprisingly found that overexpression of theNKp44-1 splice variant resulted in a significant reduction (−22.6%±3.9%)in the relative amount of F-actin accumulating at the immune synapse ininteractions of NK92-44-1 cells with PCNA overexpressing target cells(FIG. 1C). In contrast, splice variant 2 and 3-transfected NK92 cellsshowed no significant decrease in F-actin accumulation (+6.9% and +4.6%,respectively) as compared to the control WT NK92 effector cells (FIG.1C.)

To further test this finding in primary NK cells, human NK cells wereisolated from peripheral blood mononuclear cells (PBMCs) and cultured inthe presence of IL-2 or IL-15 for 6 days. Indeed, NKp44 was not detectedon the surface of resting CD3−/CD56⁺/CD16⁺ and CD3−/CD56⁺/CD16− primaryNK cells by flow cytometry, but was up regulated in the presence of IL-2or IL-15 (FIG. 2A). qPCR analysis of total NKp44 mRNA revealed similarresults to NKp44 protein surface expression. When differentialexpression of NKp44 splice variants was further examined by qPCR,NKp44-1 and NKp44-3 were both significantly up-regulated, while NKp44-2expression remained low. However, the NKp44-1 splice variant was morehighly upregulated as compared to NKp44-3 (FIG. 2B).

In a PCNA overexpression system model, IL-2 activated primary NK cellsexhibited lower lytic activity towards PCNA-overexpressing HeLa targetcells as compared to control HeLa cells (FIG. 2C, HeLa GFP vs. HeLa GFPPCNA). The same functional outcome was observed also for IL-15 culturedprimary NK cells (FIG. 2D, HeLa GFP vs. HeLa GFP PCNA). Both phenomenacorrelate with the dominance of NKp44-1 splice variant expression afterculturing primary NK with IL-2 or IL-15 (FIG. 2B). These findingsindicate that the impaired functional phenotype of primary NK cells thatresults in suppressed lysis of cancer target cells, may be associatedwith NKp44-1 dominant expression.

Example 1 shows that high expression of NKp44-1 is associated with animpaired functional phenotype of peripheral NK cells, indicatingNKp44-1's role as an immune checkpoint.

Example 2 Poor Survival of NKp44-1 Profile in Acute Myelocytic Leukemia(AML)

To further explore the physiological role of NKp44-1 in a cancerousstate, a retrospective analysis on RNA-seq data obtained from peripheralblood samples of AML, patients deposited in the Cancer Genome Atlas(TCGA) was performed. 173 peripheral blood samples that had RNA-seq datawere analyzed by first filtering the peripheral blood samples for thepresence of NK cells using expression of the NK cell-specific receptor,NKp46 (i.e. total NKp46). 164 out of 173 cases were NKp46 positive andwere chosen for further analysis. From the 164 NKp46 positive cases, 31%were NKp44 positive (i.e. total NKp44; FIG. 3A).

Thereafter, the contribution of NKp44 expression to the survival of AMLpatients was examined by comparing NKp46⁺NKp44⁺ and NKp46⁺NKp44− groups.Only 60 cases of NKp46⁺NKp44− and 36 cases of NKp46⁺NKp44⁺ had the “daysto death” data deposited in the TCGA. No difference was seen in thepercent survival between the NKp46⁺NKp44⁺ and NKp46⁺NKp44− cases groups(FIG. 3B).

To further investigate the role of NKp44 in AML associated morbidity,the expression of NKp44 isoforms was analyzed as NCR2 mRNA can bespliced into three different splice variants: NKp44-1, -2 and -3.

The relative RNAseq-based expression of the NKp44 splice variants in theNKp46⁺NKp44⁺ samples is detailed in FIG. 3C. Individual AML patientsmanifested a broad spectrum of NKp44 splice variants expression, rangingfrom a single NKp44 splice variant expressed to a mixed splice variantexpression profile. Nearly two thirds of the NKp46⁺NKp44+ casesexpressed only the NKp44-1 splice variant (FIG. 3D). Thus,NKp46⁺NKp44-1⁺-only were considered as samples having a NKp44-1 profile,whereas the NKp44-2/3 profile was defined to include all other NKp46⁺samples, whether they expressed NKp44-2 or NKp44-3 alone, or withexpression of NKp44-1. NKp46⁺NKp44− samples were defined as having aNKp44 negative profile.

FIG. 3E shows that the survival of the NKp44-1 profile group wassignificantly lower than the NKp44-negative and the NKp44-2/3 profilegroups. To better characterize the association between NKp44-1expression levels and survival of AML patients, the NKp44-1 profile wasfurther divided into NKp44-1 high (top half of expression) and NKp44-1low (bottom half of expression) profiles. The inventors then plottedpercent survival of AML cases for NKp44-1high, NKp44-1low, NKp44-2/3 andNKp44 negative profiles. The percent survival of NKp44-1low, NKp44-2/3and NKp44 negative profiles did not differ significantly. However, thepatient group bearing the NKp44-1high profile manifested a significantlylower survival rate (FIG. 3F).

Example 2 shows that an NKp44-1 profile indicates poor survival ofpatients diagnosed with AML.

Example 3 Manipulation of NCR2-Based Immune Checkpoint with Anti-PCNAmAbs

Anti-PCNA mAbs capable of inhibiting NKp44/NCR2 binding to PCNA weregenerated in attempt to block the NCR2-isoform 1-based immunecheckpoint. Mice were immunized with recombinant PCNA, splenocytes fusedto myeloma counterpart and then screened for colonies positive forbinding to PCNA and for inhibiting binding of NKp44 to PCNA.

Only two clones were able to block NKp44-PCNA interaction: 13.10 (30%blocking) and 14.25 (55% blocking, FIG. 4A). Blocking efficacy directlycorrelated with the ability of these mAbs to enhance NK functionfollowing exposure to tumor cells (FIG. 4B, C). Note that NK cells wereeither pre-activated with anti-NKp44 (that does not block NKp44− PCNAinteraction) or with anti-NKp30. In both cases, addition of severalcancer cell lines (e.g. HeLa) in 1:2 ET ratio inhibited NK function.Addition of these anti-PCNA mAbs enhanced NK function to a level higherthan the primary stimulation (FIG. 4B, C). This indicates that targetcancer cells come with inhibitory activating signals and if theinhibitory signal (e.g. PCNA) is blocked, then the NK activating signalmediated by the cancer cell contribute to NK function.

Example 4 Sequencing the Light and Heavy Chains of the Anti-PCNA mAbs

RNA was extracted from the hybridomacell pellet using TRI Reagent (SigmaCat. T9424, Lot. BCBQ3717V). Following visualizing of the extracted RNAintegrity by agarose-gel electrophoresis, the RNA was used for cDNApreparation using SuperScript First-Strand Synthesis System (InvitrogenCat. 11904-018, Lot. 1404272) with random primers and oligodT. The heavychain was amplified from the coding region by PCR reaction using primersthat targeted the constant and variable region separately. The lightchain was amplified from the coding region by PCR reactions usingdegenerated-forward primers target the N-terminal sequence of thevariable region and reverse primer that targets the respective constantregion (FIGS. 5A-B). PCR products were visualized by agarose-gelelectrophoresis, and the corresponding bands were extracted from the geland taken for sequencing analysis. Sequencing was performed on ABI3730x1genetic analyzer according to SOP 11-001 using BigDye V1.1 chemistry andsequencing files were generated (AB1 and SEQ). When no bands wereobtained by PCR reaction, new primers were designed to amplify therelevant regions of the heavy and light chains and sequenced asdescribed above. DNA sequences of the heavy and light chains wereanalyzed to yield the respective protein sequences using IMGT databaseand/or ExPASy tool.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the invention that others can, by applyingcurrent knowledge, readily modify and/or adapt for various applicationssuch specific embodiments without undue experimentation and withoutdeparting from the generic concept, and, therefore, such adaptations andmodifications should and are intended to be comprehended within themeaning and range of equivalents of the disclosed embodiments. It is tobe understood that the phraseology or terminology employed herein is forthe purpose of description and not of limitation. The means, materials,and steps for carrying out various disclosed functions may take avariety of alternative forms without departing from the invention.

Example 5 Production of Specific Monoclonal Antibody Against MembranalPCNA

Hybridoma technology was used for the production of specific monoclonalantibodies against membranal PCNA. Immunization of five C57BL6 mice wasdone with His-PCNA (Human) in CFA as well as IFA according to theschematic shown in (FIG. 6A). During the immunization schedule at day 43serum titter of anti PCNA polyclonal antibody was checked from everymouse and two of them were chosen according to their highest titter ofthe serum antibody. Splenocytes were then harvested from these two miceand fused with SP2/0 cells for the production of hybridoma (FIG. 6A).For the screening of the antibody of interest two approaches were takenone was inhibition of NKp44 receptor binding to MBP-PCNA in ELISA andthe second was cancer cell surface PCNA recognition via FACS. From 384total PCNA positive hybridoma one clone named 14-25-9 (short for14-25-2-9) showed positive result for both screening (FIG. 1B-C). Usingthe same procedure, a second monoclonal antibody was produced—13-10-1,showing comparable binding capabilities to PCNA (FIGS. 18 and 19).

Example 6 Characterizing PCNA Binding Capabilities of the 14-25-9 mAb

ELISA and western-blot were used to show significant binding of the14-25-9 mAb with recombinant His and MBP tagged PCNA, compared to anunrelated protein His-DJ1 (FIG. 7A-B). Recognition of endogenous PCNAfrom several cancers cell lines by western-blot showed that 14-25-9binds similarly like commercial anti PCNA mAb (clone PC10) (FIG. 8A).Binding affinity of 14-25-9 towards PCNA was determined using ProteOnand the KD value was found to be 3.54E⁻⁰⁸ M (FIG. 8B). In aco-incubation of 14-25-9 or PC10 with chimeric NKp44 receptor Ig, only14-25-9 showed strong inhibition of binding of NKp44 receptor Ig withPCNA (FIG. 7C). Inhibition of 14-25-9 was dose dependent, 10 μg/mlshowed the highest inhibition.

Example 7 Cell Surface PCNA Recognition by the 14-25-9 mAb

The following experiments were performed to test the ability of the14-25-9 mAb to specifically recognize cell surface PCNA. Surfacestaining of several tumor cell lines e.g., K562 in FACS showed that14-25-9 recognized cell surface PCNA where commercial clone PC10 showedalmost no surface staining (FIG. 9). When intracellular distribution ofPCNA was checked in an ‘Image Stream’ experiment, the inventors observedthat 14-25-9 recognized mainly cytoplasmic PCNA whereas PC10 recognizednuclear PCNA of HeLa cells (FIG. 10).

Example 8 The 14-25-9 mAb Recognizes Non-Nuclear PCNA from CancerTissues, but not from Patient-Matched Non-Cancerous Tissues

The mAb 14-25-9 was also shown to bind to non-nuclear(cytoplasmic-membrane) PCNA in formalin-fixed paraffin-embedded (FFPE)human biopsy samples from cancer patients. In contrast, PC10 was shownto bind mostly to nuclear PCNA in those samples. Note that in matchednon-cancerous samples from the same tissue of the same patient, 14-25-9showed no staining while PC10 stained to a lesser extent the nuclearPCNA. This was observed using fluorescence immunohistochemistry ofsections from FFPE blocks for human tongue and head & neck cancers (FIG.11) and for kidney and breast cancers (FIG. 12).

Example 9 The Effect of the 14-25-9 mAb on the Capacity of Human NKCells to Act on Cancer Cells

To test the ability of the 14-25-9 mAb to activate human NK cells, thefollowing experiment was performed. Freshly isolated human NK cells wereco-incubated with different cancer cell lines from a solid tumor andfrom leukemia (HeLa, DU145, 721.221 and K562), over-night, in thepresence of 14-25-9 or IgG1 (as control). NK cells that were incubatedwith 14-25-9 showed increase in IFN-γ release compared to mouse IgG1control (FIG. 13A). Anti PCNA mAb 14-25-9 was also shown to be able toimprove the lysis activity of fresh primary human NK cells wheninteracting with mainly 721.221 CW6 in effector and target ratio of 1:3(FIG. 13B).

Example 10 In-Vivo Effect of 14-25-9 on Activation of NK Cells AgainstTumors

For in-vivo validation of the activity of 14-25-9, immunocompromisedNOD/SCID mice were used. Patient derived Xenografts (PDX) were grown inthose mice and at the same time patient's autologous CD56⁺ NK cells weregrown in-vitro in culture. When the PDX were measurable, intra-tumoralinjection of autologous NK was done and at the same time 14-25-9 wasinjected via tail vain (FIG. 14). Injected human NK cells contained bothCD56^(moderate) and CD56^(high) cells (as expected) and wereNKp44^(positive) (FIG. 15). After 6 hr, PDX were harvested, solubilizedand human CD107a expression was analyzed from gated CD56^(positive)human NK cells (example in FIG. 16). Human NK cells in the PDX wereactivated by the 14-25-9 inoculation to the tail vein as can be seen byincrease in CD107a expression compared to untreated mice (FIG. 17).

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims.

What is claimed is:
 1. An antibody or an antigen-binding portionthereof, the antibody comprising three heavy chain CDRs (CDR-H) andthree light chain CDRs (CDR-L), wherein: CDR-H1 comprises an amino acidsequences selected from SEQ ID NO: 1 (GFSFNI) and SEQ ID NO: 21 (IYAMN),CDR-H2 comprises the amino acid sequence as set forth in SEQ ID NO: 2(RIRSKSNNYATY), CDR-H3 comprises the amino acid sequence as set forth inSEQ ID NO: 3 (HPNYSGFNYPFAS), CDR-L1 comprises the amino acid sequenceas set forth in SEQ ID NO: 4 (RSSQSIVHSNGKTYFE), CDR-L2 comprises theamino acid sequence as set forth in SEQ ID NO: 5 (KVSNRFS), and CDR-L3comprises the amino acid sequence as set forth in SEQ ID NO: 6(FQGSHVPYT); and wherein said antibody or antigen-binding portionthereof binds to PCNA.
 2. The antibody or an antigen-binding portionthereof of claim 1, wherein CDR-H1 comprises or consists of the aminoacid sequence as set forth in SEQ ID NO: 22 (GFSFNIYAMN).
 3. Theantibody or an antigen-binding portion thereof of claim 1, whereinCDR-H2 comprises or consists of the amino acid sequence as set forth inSEQ ID NO: 23 (RIRSKSNNYATYYADSVKD).
 4. The antibody or anantigen-binding portion thereof of claim 1, comprising a variable regionheavy chain comprising the amino acid sequence of SEQ ID NO:
 7. 5. Theantibody or an antigen-binding portion thereof of claim 1, comprising avariable region light chain comprising the amino acid sequence of SEQ IDNO:
 8. 6. The antibody or an antigen-binding portion thereof of claim 1,comprising a constant region heavy chain comprising the amino acidsequence of SEQ ID NO:
 9. 7. The antibody or an antigen-binding portionthereof of claim 1, comprising a constant region light chain comprisingthe amino acid sequence of SEQ ID NO:
 10. 8. The antibody or anantigen-binding portion thereof of claim 1, wherein the antigen bindingfragment is selected from the group consisting of a Fv, Fab, F(ab′)₂,scFV or a scFV₂ fragment.
 9. The antibody or an antigen-binding portionthereof of claim 1, having increased binding affinity to non-nuclearPCNA.
 10. The antibody or an antigen-binding protein thereof of claim 1,having the ability to block the interaction between PCNA and NKp44-1.11. A pharmaceutical composition comprising the antibody or anantigen-binding portion thereof of claim 1, and a pharmaceuticallyacceptable carrier.
 12. A method for treating as subject suffering froma NKp44-1-cancer, the method comprising administering to said subject atherapeutically effective amount of the pharmaceutical compositioncomprising the antibody or an antigen-binding portion thereof of anyclaim 1, and a pharmaceutically acceptable carrier.
 13. The method ofclaim 12, wherein said cancer is selected from the group consisting ofprostate cancer, leukemia, Hodgkin lymphoma, non-Hodgkin lymphoma, lung,kidney cancer, head and neck cancer, tongue cancer, and breast cancer.14. A kit for detecting non-nuclear PCNA comprising an antibody orantigen-binding portion thereof of claim
 1. 15. A method of treating asubject afflicted with an NKp44-1 cancer, comprising: (i) detectingwhether non-nuclear PCNA is present in a sample derived from thesubject, by contacting the sample with an anti-PCNA antibody anddetecting binding between the non-nuclear PCNA and the antibody, whereinthe presence of PCNA in the sample is indicative of a NKp44-1 cancer inthe subject; and (ii) treating a subject afflicted with a NKp44-1 cancerwith an antibody of claim
 1. 16. The method of claim 15, wherein thesample comprises a non-nuclear fraction.
 17. The method of claim 15,wherein the anti-PCNA antibody has increased binding affinity tonon-nuclear PCNA.
 18. The method of claim 15, wherein said cancer isselected from the group consisting of prostate cancer, leukemia, Hodgkinlymphoma, non-Hodgkin lymphoma, lung, kidney cancer, head and neckcancer, tongue cancer, and breast cancer.